Make sure you have a glitch buster as you will want one with a Savox or any high voltage servo and the IX8.

As your issue seems to have started after impacts, I would look at all of your wiring first and make sure everything is tight and there is a good connection everywhere.

When it happens, do you lose steering or does the servo lock in one direction? That might help you determine if it is losing power (servo amp draw or bad wiring to the batteries) or if it is only the motor cutting out, it is one of those 3 wires or possibly your sensor cable. You may also double check your temps and make sure it is not cutting off due to temperature maybe due to lack of airflow or a failed fan.