Stack Modifier Weapon Attachments disappear in backpack

Hello,
I use StackModifier to increase the stack sizes. When I stack weapons with attachments, it works in the inventory, but when I do the same in the backpack, the attachments disappear. Is there a way around this like in the inventory? I added a picture to better describe this issue. Maybe someone has a solution for it except disable stacking (which would be possible) or blacklist these in the backpack. :)
R1q5UpGcZO5odAb.jpg

Seems like a bug. Probably with Stack Modifier, since Backpacks isn't responsible for any stacking logic. I haven't worked on any stack plugins so I have limited familiarity how to solve these sorts of problems, and no time to allocate to this unless it's determined to be a Backpacks issue, so I suggest talking to the maintainer of Stack Modifier first to see if they can determine why this happens.