What version UCSM and CIMC firmware?
Was firmware recently upgraded to get into this state (if so roll back to the prior version)?
Have any DIMMs historically experienced any corrected ECCs (if so remove that DIMM to see if that resolves the issue)?
Most often this is due to a failing DIMM but occasionally due to a firmware/BIOS bug.
Would really need logs on a Cisco TAC case to determine if either of those are your problem.
This being a B460M4, do you have a "Terminator" to split this B460M4 into two B260M4s? Not recommending as a first step but the terminator could help narrow down where the issue could be.