ok so ive been messing with my tune for like two weeks now and i cannot figure this out. every time i try to pull into a split s the back end just kicks out and it goes into this weird oscillating death roll before i can catch it. not every time but like 60% of attempts which is way too often to be comfortable with it. running betaflight 4.4 on a 5inch, filters are mostly default with a little tweak on the dterm lowpass. rates feel fine for everything else, jukes, rolls, powerloops all feel solid. its specifically this one move that kills me. anyone had this before or is my tune just fundamentally broken somewhere

sounds like your iterm might be winding up going into the maneuver. try dropping iterm relax threshold a bit or bump the relax itself, the default settings sometimes dont handle that quick pitch reversal well especially if you have any expo weirdness at the high end of your stick throw. also worth checking if your props are balanced because an unbalanced prop will absolutely make a marginal tune fall apart on fast direction changes

i had something similar on my last build and it turned out to be a bent motor shaft on motor 3, was so slight i almost missed it. wobbled fine in normal flight but anything that loaded it weird just made the whole thing go nuts. probably not your issue but worth spinning them by hand and feeling for any roughness