BUG in Linux Mint 18.3 kernel update?

My laptop was running fine and I decided to check ‘Update Management’ for updates. I went ahead and applied all of the updates and there were quite few.
I re-booted my PC and got to my logon screen and typed in my PW. The screen blink and I was back to the logon screen. I tried again with same results. I try logging on as guest and same results.
Then I try typing in an incorrect PW and the PC came back and told me it was not correct.
I booted from my Mint 18.3 USB flash drive and was able to restore the laptop using Timeshift.


I went back and applied all the updates again except for the ‘Linux Kernel 4.15.0-64.3~16.04.1’
The PC boots fine and I am able to log in.