It looks like you have an overboost condition here. Just before the throttle closes, take a look at your actual vs. target boost. The throttle seems to be closing because your actual is higher than your target. Can you log your wastegate duty cycle? Maybe you have a problem with your wastegate.
I also recommend that you watch
this video and
this video. To your point, I believe that the Vanos could also be in play here, but that's about the extent of my knowledge on this. Good luck with your troubleshooting.