Get a tactrix cable so you can log that and see what is going on. Looks like knock more than anything to me. IDK if it is keeping boost something isnt very happy at those rpm.
I am not big on the stock ECU not because it isnt really good , cause it is people are making a shit ton of power with it. I run AEM so I dont know some of the stock ecu ins and outs.
IMO , It looks like knock is happening and it pulls timing to save the motor , then once knock is subdued it starts adding timing again and that is why at the very end of the pull it starts to try and build power again.
It mite not do that all the time , but without logging it who will know!!