Sounds like was low on fluid and burnt/glazed the intermediates because low on fluid, now it takes longer for the shift to happen and you get pressure drop from the piston having to move the additional amount to make the apply. I'd pull it and and refresh Trans, may find an updated valve body if that is suspect in your opinion. Sounds like it's coming out again, regardless. Keep us posted what ya find.

 

Pretending I'm stupid when it's an easy task to compare changes between edits is real smooth of you.

Here, have some peanut hump:


Good luck fixing your problem, maybe it's something super rare that nobody has seen before.

 

Excuse me if I missed it. Do you have a video with an actual pressure gauge reading on the trans showing the main line pressures while driving? As mentioned the pressure will dip as the command happens. This is normal but will not be more than 5-10 lbs while the shift starts to happen. After this the psi reading should go back to where it was while at WOT previously.