I encountered another bug, I'm not sure if this also the same for other people, but the Magic Potion item (one that gives 25% additional Matk for 1 battle) lasts Indefinitely (the buff remains even outside of battle).
Also Sandra's Target Marked skill "Greed" with the description "Steals a big amount of gold from one enemy. Usable once per battle" can be used Indefinitely in a battle. - you can lit. get rich if you carry lots of big TP potions and spam greed in battle.
I don't know if this is helpful info or just giving Ryen more work.. If so I am very sorry.