Belt with 2 potions terminates at a stack inserter for lab insertion. Inserter grabs potion one and inserts - counter clockwise, grabs potion two clockwise inserts, grabs and holds in hand potion one, lab runs out of potion 2. Inserter has wrong potion in hand. Lab stops (obviously).
Had to replace stack inserter with bulk inserter - works with bulk.
Stack inserter pre grabs wrong item.
Re: Stack inserter pre grabs wrong item.
Post the save and state the version in the tile please, see 3638.
Re: Stack inserter pre grabs wrong item.
Ok I have managed to duplicate the problem again and save the game with the bug - I will follow the instructions and update.