I am not sure about it not being a mechanical issue. The rail pressure is in the 700s in the mid range. I would say HPFP is on its way out.
That being said, there are some pretty bad things in that tune. Base WDGC is pretty far off (low) especially near where the drop happens. Boost is over target lower in the RPM range. Load is over requested at 3670 RPM, and PID is trying like mad to reduce boost, but the throttle plate is still at 81 (which makes me wonder if the tuner removed some safeties).
What fuel are you running here? Timing is high, like 11*, I hope it is E50 or higher. I'd be logging timing corrections to look at those ASAP.
What tuner are you using? I mean no disrespect, but I'd be concerned that they dont know what they are doing. I self-tuned my car, and am no expert, but things seem like way off.