5 GHz Force 300-16 Radio Disconnecting and not Reconnecting to ePMP 3000L Sector

We just recently upgraded one of our towers to Cambium ePMP 3000L, we are using 90 degree asymmetrical RF Elements Horns.  We have roughly a dozen customers on the Cambium equipment already.

We have one CPE (Force 300-16) though that has had problems ever since installing them.  They will stay connected and everything will work great for a few weeks and then they disconnect from the AP and they cannot reconnect with a reboot.  Changing the AP and connecting to a different AP sector and then trying to reconnect back to the AP they are supposed to be on seems to fix the problem.

The CPE is about a mile away from the tower.  The signal is -63 when connected with good rates (they are on the edge of the sector, thats why the signal isn't better).  We have tried changing the radio and PoE with no success.  There is one other CPE on this AP that does not disconnect.  Both the CPEs and AP are on software version 4.4.2.

Has anyone had this problem or know any fixes?

Since it is on the edge of the sector any reason to think there is an alignment issue causing it to move off the main lobe? If you see it happen again, can you check syslog to see if there are reasons provided for the disconnect.