Disposable Template does not create a dvm

I have several disposable templates that work just fine. However, in creating new ones checking the Disposable Template check box does not cause them to spawn disposable machines. These are standalone qubes based on Debian. As an added twist, one that I created some months back to use for email suddenly, for no reason I can see, started to function as expected. I searched, but didn’t find any other queries quite like this one.

Thank you in advance.

mike

Brand: LENOVO
Model: 20HES1PW00

CPU: Intel(R) Core™ i7-7600U CPU @ 2.80GHz
Chipset: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers [8086:5904] (rev 02)
Graphics: Intel Corporation HD Graphics 620 [8086:5916] (rev 02) (prog-if 00 [VGA controller])

RAM: 16125 Mb

QubesOS version: R4.2.4
BIOS: N1QET94W (1.69 )
Kernel: 6.12.54-1
Xen: 4.17.5