Pretty much boils down to how it makes you feel. My first play through of IWD2 I figured out that if you pause the game and spam the bard song for AC I could have unlimited armor, beat the whole game by cheesing it. Still had a lot of fun and it remains one of my fondest games.
 
	As to your scenario, I would have a question. Was what happened a bug, or is that by game design? As far as I remember items should not despawn, so I would say it's not cheating.
 
	If you feel like playing that fight again is a chore or that you were cheated I wouldn't worry too much about it.