Sometimes when I try to hibernate I get a long list of outputted errors consisting of "Write-error on swap-device"

Turns out that it has to do with compcache being enabled. You can disable it as follows (the bugreport just says to put sudo in front of the command, but I found that gave me problems, so I did it with sudo su first as shown below:

sudo su
rm -f /usr/share/initramfs-tools/conf.d/compcache && update-initramfs -u
I originally read about this here:

So far this has fixed this issue for me!