Windows App-VM gets IP from Template-VM on Qube R4.2

If you manually configure your network settings to use static addresses instead of DHCP then they will stay permanently.
There are images of where and how to change them in my link:

Also there is a link to the guide where it is described how to do this:

  • In case you switch from sys-firewall to sys-whonix, you’ll need a static IP network configuration, DHCP won’t work for sys-whonix. Sometimes this may also happen if you keep using sys-firewall. In both cases, proceed as follows:
    • Check the IP address allocated to the qube - either from GUI Manager, or via qvm-ls -n WindowsNew from a dom0 terminal (E.g. 10.137.0.x with gateway 10.138.y.z).
    • In the Windows qube, open the Network manager and change the IPv4 configuration of the network interfacefrom “Automatic” to “Manual”.
      • Enter the Address: 10.137.0.x in our example.
      • Enter the Netmask: 255.255.255.0
      • Enter the Gateway: 10.138.y.z in our example.
      • Enter DNS: 10.139.1.1,10.139.1.2 (the Virtual DNS addresses used by Qubes.
    • Click “Apply”. You should now see “Connected”.