ZDoom

Is ther any flag to turn that off? Either per-item or game-wide?

That's the sprite offset adjustment at play. For pickups the rules are different because too many of them had bad offsets.

sprite TESTA0, 26, 13
{
	offset 13,7
	patch TLGLA0, 0, 0
}

class TEST1 : actor {states {spawn: TEST A -1; stop;}}
class TEST2 : inventory {states {spawn: TEST A -1; stop;}}

for example, use this sprite from GZDOOM:
[code]
sprite TESTA0, 26, 13
{
offset 13,7
patch TLGLA0, 0, 0
}
[/code]
that sprite is 26x13, and the 13,7 offset says it should be sunk into the floor when used by an actor
so I try it on both an actor and an inventory class:
[code]
class TEST1 : actor {states {spawn: TEST A -1; stop;}}
class TEST2 : inventory {states {spawn: TEST A -1; stop;}}
[/code]

And this is what I see:
[imgur]https://imgur.com/hzPpGYj[/imgur]
Thats TEST1 on the left and TEST2 on the right
I loaded radius debug to confirm it's not a positioning issue, but I still see it without that or anything else loaded