Fixed : When making more than one potion at a time, you really get 2 or 3 potions
To make 1 potion you must give x products
To make 2 potions you must give 3*x products
To make 3 potions you must give 10*x products
The quantity of products you have to give is too high compared to the number of potions you get.
If you try to make 2 or 3 potions at the time, you waste a lot of products, so those options are totally useless at the moment.