Both preference indicators of the preferred and alternate SMMs occasionally light on after the chassis is powered on (or after an SMM is removed and then inserted), while the management network port indicators remain off, hindering the troubleshooting through the network port.
Remove and insert each SMM for once by connecting them to the chassis at normal speed.
However, SMM suspension occurs when the SMM is inserted at faster than normal speed.
Previously delivered SMMs whose PCB version is B introduced a bug; that is, occasional suspension of both SMMs due to short remove-and-insert interval or consecutive power on and off.
To completely correct the problem, replace both SMMs with the ones whose PCB version is C.