Tested with 5.8.0-050800-generic downloaded from kernel ppa. Got exactly the same error as above, except this time the whole system froze and became unusable, so I had to kill the power to the PC.
Additionally I got a whole bunch of new errors in dmesg like
Tested with 5.8.0-050800- generic downloaded from kernel ppa. Got exactly the same error as above, except this time the whole system froze and became unusable, so I had to kill the power to the PC.
Additionally I got a whole bunch of new errors in dmesg like
[ 31.072963] SQUASHFS error: Unable to read metadata cache entry [31b7fff]
[ 31.072964] SQUASHFS error: Unable to read directory block [31b7fff:13ee]
which seem to be unrelated.