Spellthief's Edge BUG

For a couple of times almost every game Spellthief's Edge ability don't register auto attack or Zilean's bomb as a hit. It doesn't matter if there are 3 or 1 charge left on Spellthief's Edge, sometimes it just ignores it and gives no money as if there was no hit at all yet the hit does damage to opponents. Bug happens by playing Zilean as support on EUNE, sc2salt