car used to cut fuel on the shifts. now it doesn't(boosted)

I am getting a backfire or two on the shifts. i am seeing negative timing numbers at the shift and i think that combined with no fuel cut is causing the backfire.

i have logs when it was stock on gasoline and then mostly stock but with e85 and it was still cutting fuel then but now with some boost it no longer cuts the fuel.

any idea how i get that back. i tried going back to my old tune other than a couple of setting like injector size and maf table and that didn't bring it back. i suspect it is an air mass thing but i cant find anything obvious.

post tune for more help

Can take minimum timing table at your shift points and add timing there. On my 16 vsport it had -20 I put 6 in it just to be safe and not only didn't back fire anymore or pop at all but shifted firmer too.

Did you re-enable DFCO after tuning?