UPS/batt mods vanish from firearm kit when put in same pile as reg firearm kit

Win 10 x64, Tiles, build 6784,

If you try and add a UPS mod to a firearm repair kit, while having a stack of 3 on the ground next to you, it says “you attached your UPS mod to none” and the UPS mod disappears and the firearm kit does not change into a modded one. Seems you have to separate one from the stack in order to add the mod. I believe adding a modded firearm repair kit to the stack removes the mod as well, as I had one with a battery compartment mod, but it is no where to be found, which is how I encountered this bug after looking for my firearm repair kit to top off my guns, not being able to find it I decided to just add a UPS mod to one of my spares and this bug happened.

edit: found it, but still lost a UPS mod due to it being attached to none.

OK apparently I did not lose the firearm kit with extra battery mod, I just misplaced it. The UPS battery mod gets attached to none, is a bug I believe howeever, and have had it happen in the past before this current run, but wasn’t fully aware of how it happened in the past until this most recent time.