RE: CC BEC causing interference or damaged?
the red wire from the esc is basically the output from the BEC circuit inside the esc. By cutting it you simply are keeping the esc from providing power to the receiver. I can't remember for sure but doesn't the CC bec have a three wire plug going to the rx as well? IF so, you can remove the orange wire from the bec plug. The orange should be your signal wire and you could try taking that out as well but I doubt that it is going to make a difference.
For my purposes, I never cut any of those wires. I used the shortest extensions I could find and cut the wire out of the extension that way I wasn't changing the electronics where I couldn't have them like they were from the factory. On my MT though, I removed the red wire from the esc and the orange from the bec. I had to because I was going with a spektrum rx and if I didn't do it that way the rx always wanted to go into bind mode. I am doubtful that either of these items are the root of your problem.
does it do this anytime it is powered on or only while the blades are turning?