Invalid LUID

Got an error in the event log on a PMP 100 5.4 FSK AP in regard to a specific customer. the error goes like so:  "Invalid LUID 0 Calculated from SM_ESN 0A-00-3E-**-**-**" I have had the customer power cycle their equipment and I have cycled the AP, the error has yet to re-occur, but now the customer reports  they have no connection and I do not see they have another session at all, I have waited the 10-15 min req peroid.. nothing. I will go replace the radio, just wondering if anyone else has seen this error?