Haven't had that issue running a straight 2S Lipo on either of my N7s. Haven't heard if the BK servos do the same thing but I'm putting a set on my E5 with a Scorpion Commander 130A SBEC, so I'll find out soon.
Apparently Bert has worked directly with the manufacturer that makes the rjx (yes rjx is just an oem of another brand) and has a different setup in his. Narrower dead band, smoother gear train and a different motor controller so his servos shouldn't do this.
I am going to stop saying they are the same as rjx because they really aren't now. First run of minis were but the full size is in fact a different servo. Same factory different materials and qc standards.
I have a set on my e5 12s. Going great. No issues with my cc bec pro.