Well, mine doesn't seem to have this problem.
The only thing I did was to lean the low end a bit, because as set from DA, it was way too rich. I also made sure I had an exit air opening so as not to have a lot of turbulence right at the carb.

I only have about 4 tanks through it. I don't have any hills, but I will try abruptly stopping it and lifting the tail to see if it will do the same.