I was hoping it wouldn't come to that. I did fully recharge the battery, (it was at 7.6v, still more than enough) and it went away for now. But if it is indeed overstressing the Bec, I won't keep running it. I'm probably just going to swap servos to save weight instead of running an external bec until I can get my hands on a tekin rs pro which is the esc I originally wanted.