Interesting.
I've thought about the possibility of the exhaust pressure rapidly reducing when the throttle is slammed shut or when the clutch is depressed, engine load rapidly reducing causing this.
The smoother TP% decreases the smoother AFR ramps back to commanded.
It's more pronounced when shifting gears during PE,
AFR gets quite rich but it's better than having DFCO on and
the harsh re-engagement of the clutch.
It may not be that big of a deal, LTFTs and PE AFR are where I want them
it just makes a log look a little ugly.