Dear All
this problem can accour when you have difference between the main and diversity RSSI ( TRX level in the same sector)and this difeerence its more then 3db , and the problem in this case maybe in your TRX or feeder or connector so you have to check with site master ( VSWR, and DTF)
DTF should be less than 1.05 in connector and 1.03 in the feeder