Matt_Nico One additional weird thing which is occurring on my desktop is that I will sometimes be unable to log in from the lock screen after the computer has gone into standby mode. There will be no option to type in the field where I must enter the password. This behaviour stops if I log out of the account and then log back into the system. This happens when the system is left in standby for longer than 6 hours, so I had just switched to powering off my system when this behaviour occasionally flares up (usually it will happen a few days in a row and then I will switch to powering the system down. I don't think this would be related.
I actually also have this issue, but I usually resolve it by hitting "Switch User" and then logging back in. It kicks you back to the standby screen, but then password entry works. So I don't think this is related to your primary issue.
The /home failing to mount, alongside the boot manager issue, would lead me to think there's a problem with the storage device. But the fact that it's replicated across both systems should rule that out. The odds of two drives failing in exactly the same way at exactly the same time in two separate systems are basically zero.
Your issue seems to be beyond my knowledge to troubleshoot. I don't see any issues in your kernel logs either. This sure is a puzzle. If I think of anything I'll pipe in, but I'm not sure how to help you at this point. You need someone more experienced than myself.
