I have a few Dell Latitude laptops - E7440, E7450, E7470 and 7490 - some have keyboards with lights under them.
The ones with the keyboard lights sometimes hang with the display showing the it was saving the keyboard light status.
You have to power off and back on to get out of this - to make matters worse - it you touch the keyboard on boot up - it seem to hang almost every time.
Anyone else see this - Sometime the caps lock light get turned on on the hang.
I’ve been reading about a long-standing bug that affects some Dell hardware with respect to a buggy driver and it’s handling of keyboards with/without keyboard backlights. Now, I’m not certain that the issue you describe is related to this, but in any case some users have found that inhibiting a particular systemd service provides a userspace workaround for what is suggested as a kernel-space driver issue (yet to be resolved). FWIW…