my understanding is that there were 2 recent incidents which prompted investigation and discovered a fault with the iridium system. One in which a crew executed a climb instruction issued but not delivered to the same airframe on a previous flight, and a similar one where an instruction was recieved on the flight deck but unable to be executed and subsequently queried and investigated. Sorry i can't provide more detail - quite likely that other FIRs will follow suit until a fix is inplemented.