Morg Passive Bugged?

I just got out of a game where I played Morgana, and checked my "damage healed" out of curiosity (knowing that her passive gives her spell vamp), and I was shocked to find that I healed....LESS than 500 damage? I felt like I wasn't healing much during the game, either, which is one of the reasons I checked. Is this a bug with the after-game screen/match history (both showed under 500), or with the champion?

Here's a link to the match history showing my damage done/taken/healed, etc.