Today with my L3+ I had a failure in the chain #4 I got 6 "x" but when I reboot it they disappear but HiveOS sends error and 5 "x" appeared again I have no idea if I should be worried or what could it be.
Example Image:
https://ibb.co/54zS7zkdrop the clock from 612 to 580 see if it holds the board.
either the board is tired of freq 612 or the psu is aged a bit or both.
how long have you run at 612?