Specifically the two that I found are the Yammo weapons and the Quetzi Headpiece.
I'm not certain that it's on_stacks_changed_fn, but that seems to be common between the two, and while probably not a good solution, adding the modification to on_add_fn seems to fix it, since it's called at the start of every room.
The modifications in on_stacks_changed_fn seem to only apply in the Town and the first room of a hunt (so when the weapon is equipped).
It's easiest to see on Yammo.
Spawn like 11 enemies in the town, and use Yammo Slammo on some. They'll deal damage as they fly into the other enemies.
Same thing in the starting room of a hunt.
In the next room, flying enemies no longer deal damage.
Same thing with the Quetzi Headpiece.
I wrote this into the console to print the luck values:
for _, player in ipairs(AllPlayers) do print(player.name,player.components.lucky:GetTotalLuck()) end
A developer has marked this issue as fixed. This means that the issue has been addressed in the current development build and will likely be in the next update.