HPFP drop off & vacuum instead of boost when on WOT

Hi- Please help with intermittent HPFP drop offs & vacuum in manifold instead of boost when on full throttle. I have highlighted the HPFP readings in red where the problem occurs. This happened on the track at Eastern Creek at the end of the day. I am unable to replicate the issue on the road. I thought it may of been fuel surge but it did not feel like it. I have experienced fuel surge before but the fuel light was on before. This time I had another 25L left in the tank. It feels like boost cut.
Any ideas. Could the PCV valve be the culprit ?

Your realative throttle is at 8% in one cell with app of 99%, forget about what your foot is doing. One of the gurus will be able to help ya. Reading from ifail is a mole but from what I can see maybe your hitting the throttle close limit on map, look in your maps to see what the limit is set at and at what point the throttle is shutting in this log.

Fuel pressure should never drop to those levels even at idle. Something wrong for sure, could be your relief valve opening up which is dropping the pressure. Any strange sounds coming from your pump area?

No strange noises.

I thought I will update my findings on this. The last track day I kept the fuel above half way. Had no issues. So I expect I must of had fuel surge with 25L left in the tank before. HPFP drops were caused by fuel surge, relative throttle closing to protect motor & waste gate duty to O% all to protect motor from HPFP readings below 400. I don't know why I had fuel surge at these levels where as before never experienced till the low fuel light came on.