Setting "maxmem" from SaltStack

I’m working on encoding some of my setup in SaltStack and I come across an issue. I can’t set maxmem from SaltStack. If I set it with qvm-prefs works fine, but then I apply the state, and the SaltStack clears the setting.

{%- from "qvm/template.jinja" import load -%}

include:
  - sys-usb.tpl.at-dom0.create-tpl-dvm

{%- set qube_name = pillar.sys_usb.qube_name %}
{%- set tpl_name = pillar.sys_usb.template %}

{% load_yaml as defaults -%}
force: True
require:
  - qvm: "sys-usb.tpl.at-dom0.create-tpl-dvm/{{ tpl_name }}-created"
name: {{ qube_name }}
present:
  - template: {{ tpl_name }}
  - class: DispVM
  - label: red
  - flags:
    - net
prefs:
  - netvm: ""
  - virt_mode: hvm
  - memory: 600
  - maxmem: 3000
  - provides-network: false
  - vcpus: 2
  - autostart: true
service:
  - enable:
      - qubes-usb-proxy
  - disable:
      - network-manager
      - meminfo-writer
{%- endload %}
{{ load(defaults) }}

I tried also bare qvm.vm but result is same.

[greg@dom0 ~]$ qvm-prefs  sys-usb                                                                                      
audiovm             -  None
auto_cleanup        D  False
autostart           -  True            
backup_timestamp    U                                                                                                 
debug               D  False                                                                                          
default_dispvm      D  tpl-sys-usb-fedora-41-dvm                                                                      
default_user        D  user      
dispid              -  8289                                                                                           
dns                 D                                                                                                 
gateway             D     
gateway6            D  
guivm               D  dom0                                                                                           
icon                D  dispvm-red               
include_in_backups  -  False                                                                                          
installed_by_rpm    D  False            
ip                  D                   
ip6                 D                   
kernel              D  6.12.25-1.fc37
kernelopts          D  
keyboard_layout     D  pl++
klass               D  DispVM                                                                                                                                                                                                                
label               -  red
mac                 D  00:16:3e:5e:6c:00                                                                                                                                                                                                     
management_dispvm   D  default-mgmt-dvm
maxmem              -  3000
memory              -  600       
name                -  sys-usb
netvm               -  None                                                                                                                                                                                                                  
provides_network    -  False                                                                                                                                                                                                                 qid                 -  63                                                                                                                                                                                                                    qrexec_timeout      D  60
shutdown_timeout    D  60
start_time          D  
stubdom_mem         U
stubdom_xid         D  -1
template            -  tpl-sys-usb-fedora-41-dvm
updateable          D  False
uuid                -  68de91b1-0e9b-4ef8-ba9a-8c727e32710f 
vcpus               -  2
virt_mode           -  hvm
visible_gateway     D  
visible_gateway6    D  
visible_ip          D  
visible_ip6         D  
visible_netmask     D  
xid                 D  -1

// then apply

          ID: sys-usb                                                                                                 
    Function: qvm.vm                                                                                                  
      Result: True                                                                                                    
     Comment: ====== ['present'] ======
              [SKIP] A VM with the name 'sys-usb' already exists.                                                     
                                                                                                                      
              ====== ['prefs'] ======  
              [SKIP] autostart          : True                                                                        
              [SKIP] virt_mode          : hvm                                                                                                                                                                                                
              [SKIP] maxmem             : 3000                                                                        
              [SKIP] memory             : 600
              [SKIP] netvm              : None
              [SKIP] provides_network   : False                                                                       
              [SKIP] vcpus              : 2                                                                           
                                                                                                                      
              ====== ['service'] ======       
              [SKIP] Service already in desired state: ENABLE 'qubes-usb-proxy' = Enabled                             
              [SKIP] Service already in desired state: DISABLE 'network-manager' = Disabled                           
     Started: 12:56:54.371663                                                                                         
    Duration: 540.848 ms                      
     Changes:                                                                                                         
              ----------                                                                                              
              qvm.service:                                                                                            
                  ----------                                                                                          
                  qvm.service:                                                                                        
                      ----------                                                                                      
                      meminfo-writer:                                                                                 
                          ----------                                                                                  
                          new:                                                                                        
                              Disabled                                                                                
                          old:                                                                                        
                              Missing 

          ID: sys-usb                                                                                                 
    Function: qvm.vm                                                                                                  
      Result: True                                                                                                    
     Comment: ====== ['present'] ======
              [SKIP] A VM with the name 'sys-usb' already exists.                                                     
                                                                                                                      
              ====== ['prefs'] ======  
              [SKIP] autostart          : True                                                                        
              [SKIP] virt_mode          : hvm                                                                                                                                                                                                
              [SKIP] maxmem             : 3000                                                                        
              [SKIP] memory             : 600
              [SKIP] netvm              : None
              [SKIP] provides_network   : False                                                                       
              [SKIP] vcpus              : 2                                                                           
                                                                                                                      
              ====== ['service'] ======       
              [SKIP] Service already in desired state: ENABLE 'qubes-usb-proxy' = Enabled                             
              [SKIP] Service already in desired state: DISABLE 'network-manager' = Disabled                           
     Started: 12:56:54.371663                                                                                         
    Duration: 540.848 ms                      
     Changes:                                                                                                         
              ----------                                                                                              
              qvm.service:                                                                                            
                  ----------                                                                                          
                  qvm.service:                                                                                        
                      ----------                                                                                      
                      meminfo-writer:                                                                                 
                          ----------                                                                                  
                          new:                                                                                        
                              Disabled                                                                                
                          old:                                                                                        
                              Missing 

Thoughts?

Because the qube is already present and with the desired configuration?

This is because you are disabling meminfo-writer, which disables dynamic memory
management.
What do you think maxmem would represent in this case?

I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.