Lean at WOT

Hello all, I've been chasing this issue for about 2 months now, car cruises just fine, AFRs are at 14.5-14.8 out of boost, cruising anywhere from 40-80mph.... No problem, now when I give it WOT on a pull and starts boosting the AFRs want to jump up to 15-16... However, if I ease into boost I can see 12's, problem is when I aggressively go from cruise to WOT, it hates it, starts hesitating and sputtering.

Mod list:
-FMIC
-BNR S4 turbo
-HPFP
-Freshly cleaned and tested injectors with all new seals.
-JBR 3.5 intake
-Docrace tubular exhaust manifold
-3" DP to straight single exhaust
-Oil catch can
-Turbosmart BOV
-PD tune.
-Crate motor from Mazda with about 40k miles on it.

Car was tuned before I got it, I don't know how long ago could be anywhere from 1-3 years ago, the tune supports every mod on my list, I haven't changed anything except for the BOV and cleaning the injectors plus all new seals. (CS seals). Idles fine, STFT usually fluctuates from -3 to -15. On a cold start it will be in the -20s
LTFT usually hangs around -2 to -4 on idle.
Fuel pressure is in the 1800s during WOT.
I cleaned the injectors and changed bov thinking that was part of the issue, but the car still does the same thing.


I've send data logs to the tuner and I'm being told there's a vacuum or exhaust leak somewhere.... I've looked, and looked, can't find any, I've done smoke tests, pressure tests (holds 25psi) and can't come up with anything. Fuel is there, O2 sensor is new, MAF has been cleaned.
Could the MAF be going bad?
Anyone else go thru this?
Im New to this platform, seems like a fun but peculiar car. I'd hate to mess it up it's got a lot of potential, just need to get it dialed in better.
Any help is appreciated.