M365 automatically reverts back to an older version

Here you go:

Hi, I would start checking these points:
1. Have the Microsoft 365 Apps been deployed using Intune as native M365apps? Might it be that a specific build was selected and now Intune is enforcing said build?
Verify if the device is targeted by Intune with a native M365Apps deployment. If yes, check if the app is configured to be on a specific build in Intune (opposed to being on 'latest'). If this is the case, switch the build to "latest" and save the config.
2. Is "targetversion" set? Search the HKLM\Software registry hive for "updatetargetversion". Is there a hit in a subkey of HKLM\Software\policies\? Then a GPO is setting the targetversion. If the hit is somewhere else, the targetversion might have been set by ODT.
Bonus: Also search HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\Configuration for the build number the device is currently on (16.0.xxxx). Is there a key called something like "updatetoversion"? If yes, this has been set by ODT as well and is keeping the device on this version.
For the latter two issues, the solution is to rename the registry key, restart the C2R service and trigger the update. The device should now update to the latest build and stay there.
If none of the above yields any results, you need to start digging deeper into the logs to understand if the rollback is an update or install action. And then who/what could trigger that.