I am running EOS 5.1 in VirtualBox (also has it on a Laptop but I usually use VirtualBox to test upgrades before applying to Laptop).
See Keyboard -> Shortcuts have valid values before update:
I checked App Center there was a Keyboard 2.3.6 update. I clicked Update.
Immediately afterwards, Keyboard -> Shortcuts are completely Disabled. No way to re-enable them!
Is this happening only to VirtualBox VM?
If this happens to bare metal it would be a very serious problem.