There's a bug where if you save your game with a love potion but then reload that save file, the love potion is gone and I think it also takes away the materials used for the love potion? I had like 6 on me so that I could test them out on different people/enemies but then I reloaded my save file right after I had gotten the 'Mastered Potion' tier for the Love Potion and not only were all of my Love Potions gone but also the MP tier as well