As the title says, but you would not be allowed to take that mag from your weapon anyway so it causes no harm to your newest mechanic.

It is just in generall very annoying that you don't see your items that are stored double layer deep.

(For gun mags it is especially annoying and confusing sometimes)

But please consider changing how this mechanic works, so that those items don't disappear from the hotbar; why would they anyway - this is very odd solution to apply this mechanic.

Instead add a check flag whether they are double layer (or as active mag) stored, and just apply RED COLOUR to the item on a hotbar, and block the action by a simple check.

This gives players way more feedback and understanding of what they carry.
Sometimes you just hide valuable stuff 2 layers deep to not lose them → there comes a fight and you just forget about them when you have to strip or sth., where you would normally have had them on the hotbar to NOT forget them.

Simple solution, nicer approach → no cons only pros.