On the very first main quest, the player is tasked to land on Kreet, in order to "take care" of a pirate boss. On my playthrough, I focussed on the actual mission first, i.e. I killed the pirates and didn't look for loot elsewhere. I only looted the prirates and some of the dead scientists, then left the interior cell and fought the prate boss on the roof. I then fast travelled back to my ship to drop my items into the cargo bay and subsequently returned to the research facility to search for more loot.
At this point, I noticed that all of the dead pirates had full inventories again (i.e. weapons, ammo amd - occasionally - extra stuff), even though I looted most of them before and they had nothing left in their inventories. This only affected the pirates; the dead scientists were stilll empty.
BTW, I doubt that this only happens in the research facility on Kreet, but I'm still very early in the game.
Issue Data
Issue #33586: Dead pirates inside the research facility on Kreet respawn their inventories on cell reload