fuel cuts?


Ready to race!
2006 gti mkv
So I searched but couldnt find anything similar to my case so here goes.

Coming home on the highway this morning I was checking my boost too make sure the catch can i just installed is holding up properly. I was in 4th gear around 4000 rpms and went wot, watching my boost climb up to 21psi then it would jump down to about 17psi then jump back up and hold normally. When the boost is jumping I heard a noise from the exhaust almost like a dsg fart but shorter. I was able to replicate this several times in 4th gear but when I went to 5th it didnt do it. I tried to check out 3rd gear but it was like 10 degrees F outside today so I couldnt get any traction.

I had sever misfire issues in the past but havent had any for about 6 months because an injector was replaced to fix the problem. But this doesnt seem like a misfire, its similar but different too.

I just got my car back from the body shop 2 weeks ago( front end damage), and they put on a new radiator, ic (upgraded to s3), and condesor. Like I said I recently installed the VTA bsh catch can on friday too. I'm Unitronic Stage 2 93 oct. Rest of mods are in my sig.
Thanks for any help!

note: this happens real quick when at wot. it only lasts for a second then it pulls to redline normally. I have a bottle of techron left over so I might throw that in but I really dont think its misfires but what do i know haha.