Their registration was good until sometime in 2015 if I remember correctly. No suspension of that tail number would occur until AFTER the renewal date unless, sold, scrapped, or crashed. If not informing the FAA was standard, the Tail Number would not be even be considered for reuse until after the expiration of the certificate. The FAA can not just zap a current registration, Tail Number for nothing and give it to someone wanting to register a plane.
If that’s how the FAA works, just zapping numbers that are currently registered without due process, that is screwy and certainly not proper for public safety.
Leis transferred the tail number to another one of their planes. No big mystery.