The PMU FW can initiate MBIST operations on the LPD and FPD; however, the LPD process does not affect the PMU RAM in the LPD. When a memory is tested or cleared using an MBIST operation, other parts of the system can be functioning.
If there are no errors after boot, means the PMU_ROM was successful in clearing all of the memories. After boot, the only confirmation available to users is whether or not the MBIST failed and which domain that memory resides (LPD or FPD).
MBIST failure is registered as PB_ERR and it doesn't halt the boot unless a specific eFUSE is programmed.