Could you check the value of TCH FAIL per TRX ? Also, try to tell me the amount of traffic (erlang) per TRX.
if you see one TRX only have poor TCH Fail, lock it and check TCH FAIL tomorrow.
if all TRX have poor TCH FAIL : deactivate frequency hopping, and check again, per TRX.
But before all, please write down the values I asked above, per TRX 🙂