Savox servos are very demanding on power. You need to put a cap/ glitch buster on your rx. It will eliminate you problem.
What is happening, is when your servo is used it sucks the power from the Rx at suck a high rate it will lose its bind to the Tx for a fraction of a second causing you glitch. Its not enough to completly shut the system down, but it will play havoc with you.
Get one of the Spektrum one for like 5 bucks and plug it into an emtey slot on your Rx. If you dont have an empty slot, you will need to solder it in. I would recomend putting it on the switch harness that plugs into your Rx. Dont put it on the battery or before the switch as it can charge up and zap you. Also dont put it on a servo wire. Hope you get it working.