sorry,,, dont know if it has been reported yet.
when i buy items (well i only buy potions, so not sure about other items), say i want to buy 50 potions, then sometimes it will be stuck after i bought 31, and says fail to buy the item. then i would have to talk to npc again and it might get stuck again. this is very annoying. and most importantly, my money still goes away, while it says "fail" and nothing goes to my bag