For HO,RxQual has the more priority then Interference.
Network will set the HO cause as follow:
rx_qual HO allowed? -> check rx_qual thresold ->interference_HO allowed?(if yes,then it will check for intracell_ho threshold,if rxlev greater then the threshold then ıntracell ho will occur.otherwise not and HO cause should be rx_qual)..(if interference_HO not allowed..then set the cause Rx_qual and intercell HO will occur).
So its amazing that ur interference ho are disabled but they are occurring.