It appears that there are two issues, but they may be related.
Ubuntu 18 is not shutting down properly. When running sudo shutdown -P now, it begins shutting down, but gets stuck at the screen with an Ubuntu logo and five dots (progress bar). It gets stuck after completing the third dot. It appears that the coolers no longer run at this point. To proceed, I have to hold the power button and shut the machine down.
Ubuntu 18 is not hybernating properly. When sending it to hybernate, I can see that the screen turns black; however, the power light stays on. I can also hear the coolers run. I am unable to bring the machine back from hybernation and have to manually reset it using the power button.
I tried tweaking a couple of GRUB settings, but that didn’t help.
Could someone tell me how I can fix this? Tha machine is a Lenovo circa 2014, 2015.