Reverse Thrust issue/question on e-Flite V1200

[AilerRon]

I have had three E-flight V1200s. When I setup Reverse Thrust, it appears to work but if you throttle up too quickly the motor makes a clunk noise and shuts off. The servos still work but the motor will not run until you disconnect and reconnect the battery. Even if Reverse thrust is not requested, the motor can still shut down if accelerating too quickly. This has caused a couple mishaps while flying. If I go into my ESC settings and disable Reverse Thrust, then there is no issue under normal flying conditions. I am hoping that software updates to my Spektrum Dx9 and the AR637TA receiver in the V1200 will correct this. I've spoken to Horizon Hobbies tech support several times and sent them a video that displayed the behavior, but they have no good answers as to why this behavior would occur. Has anyone else seen this behavior involving Reverse Thrust on a V1200 ? Thanks