RAM usage in Supervisor "System" tab

After some serious troubles I had to reinstall Raspbian and HA (Supervised installation in Docker) on my Raspberry Pi 4B. After restoring a recent backup everything worked as expected, but I don’t see RAM usage neither for Core nor for Supervisor anymore on Supervisor “System tab” - it just shows 0. On my old installation it worked flawlessly.


Any ideas, what would I have to do to make it work again?

Not sure it’s related, but there’s another issue bugging me after reinstall - when performing manual backups, it seems that it takes a lot more time than it used to and after some time I get this on the screen:


The backup is created normally despite of all this, just the error pops up.

Is it possible, that Supervisor is missing some priviliges or smthg similar? Therefore has no access to RAM usage and at the same time has troubles creating/saving backup?
Any suggestions on how to deal with it?

Turns out to be a kernel issue on RPi…

If anyone interested, solution here.