this bug happens sometimes when im in the middle of building my craft, the mirror tool would mirror the part on the other side at first, but when the you release the part and it snaps in place, the part on the opposite side would not show. the bug would usually affect parts that were mirrored previously or when a new part is placed on another part that was already mirrored. the only way to get the part working again is to either refresh the alp or go back to the menu and rejoin the building pad.
