Update i talk with cambium and manage to get a remote session with them they conclude to a hardware problem and ask for rma... They said the same thing last year about the same problem. I swap the the radio but got the same results. But i was sure that isn't the case is a software problem. So i continue my investigation... I use this ptp link to transport a vpls tunnel contain pppoe traffic between two mikrotik via a vlan. So i upgrade the mikrotik pppoe server to the last version and now i got a different problem... i didn't get rx stuck now but the bridge seem to be stop working after a day... The ap and the sm still work i can see from the mikrotik the ap and the sm from each side but the two mikrotik stop seeing each other....