Unofficial Fallout 4 Patch

Some raider corpses of Pack, Disciples, and Operators in Nuka-Town USA don't despawn after killing them and completing the quest Open Season. Current corpse count upon return to Nuka-World after 31 days of waiting at Sanctuary: Shank, 3 Packs and 1 Operator corpses outside of Market, plus 1 living Operator who seemed to have respawned. Mags plus 2 Operator corpses in Parlor. Cappy's Cafe and interior of Market are clear of corpses. Mason plus 2 Pack corpses in Amphitheater, plus one living pack dog that respawned. 2 Pack corpses in Backstage section of Amphitheater. Nisha and 2 Disciple corpses in Fizztop Mountain. Even Overboss Colter's body is there in Nuka-Cars. I will note that I had left Lizzie, Dixie, and Savoy alive in my playthrough and killed just the bosses and all the generic raiders. Mods I had active: Unofficial FO4 Patch, Cheat Terminal (only use it to spawn weapons/armor and for leveling, didn't do anything I thought might interfere), Loyal Porter Gage (so didn't kill Gage). And I did Open Season right at the start of Home Sweet Home (killed Shank first)

Someone else's observation:

There are always two corpses never get despawned or cleaned up properly if you do this quests. The bodies of Mason, Mags Black, Nisha, Shank, Lizzie, Gage and Dixie never disappear. That's okay probably because they are main characters. William Black's body will disappear.

But there are always two corpses stay on forever. 2 in the market, 2 in Nuka Town Usa just outside of the market, 2 in Nuka Town near the pool in front of Fizztop Mountain, 2 in the cafe, 2 in Bradberton Amphitheater etc.

I actually tried the cafe fight 2 or 3 times for some reason. Each time leaving Nuka-World then came back, the cafe always remained 2 corpses never got cleaned up.