I should've playtested more, I had only gotten this null bug once during development but apparently it's got something to do with having an extra gun early on for some reason. It probably doesn't add or remove anything if you select it as null though, I'd bet the guns just look like a single gun sometimes when both are shooting in the same direction (which is something i kinda didn't know how to avoid completely :/).
I'll look into solving that, thanks for playing and for leaving feedback! :)