So this TX/Rx combo has been working in the buggy with the Protek servos before? Or is this a new combo? What are you running for a receiver pack? Obviously checked and charged properly I hope...

Sounds like it could be a brownout, servos could be drawing an excess amount of juice from the receiver. Never heard of Protek 300T's before but whatever....they could be faulty internally. Different receiver, servos or maybe a $5 capacitor or "glitch buster" as some call it might fix the issue.