You can check the log as to when the system checks for a firmware update. If you had it toggled on, you could set the time for it to do that. You might try turning it on, setting a different time and then place it back to off.
Having several Mesh nodes
may effect its behavior although mine just flashes the bell if a Mesh node needs an update. I suppose there may be a limit how long an update can be available before it overrides your update selection.
I have my system disabled and it has not been doing auto-updates.
Maximus Z890 Hero,
Intel Core Ultra 9 285K