I discovered what I think is a duping bug, but I haven't been able to replicate it since the first time.
The first scenario went like this:
I placed 4 turrets near a biter base using the Krastorio early game construction drones, placed ammo in them and let them work.
At some point I ordered a deconstruction plan on them.
2 of them must have become damaged at some point before the drones picked them back up, as I suddenly had 6 turrets in my inventory. 4 normal ones, and 2 damaged ones.

Edit: I DO have a bunch of other mods running, but other than Krastorio none of them should interact with the turrets or drones.

Not related to K2, look for other mods in ur modpack

Not related to K2, look for other mods in ur modpack

Maybe, and I've not been able to replicate it since with any kind of bot/drone building, and the 6 turrets turned into 4 turrets again later on somehow so I don't know, lol.