Welcome to the forum.
I've had similar issues with different tunes I've tried. For me, it would feel like a flat spot. My problem would actually be on the low boost/rpm side. I'm not sure, but maybe it's possible that the car is still learning. I've attributed the flat spots to the car being used to WOT, and predicting such conditions. For example, it is expecting me to drive aggressively, so when I'm not accelerating hard, it's not sure what to do haha.
Depending on how you drive, maybe it's just the computer learning (new driving conditions + environment)?? But again, I'm just guessing. Without any videos or engine codes, it's hard to say.