Less HP than I had yesterday?

After leveling during double experience, I ended up with exactly 13,000 unbuffed health - right on the dot. This is why I remember it so well.

I've been staring at it like that for a few days now.

Tonight when I logged in I noticed my unbuffed HP is 12,853. I haven't changed any gear, links or character cards. I've triple checked. All I've been doing everyday is running Gollux, Commerci, One-card and logging out.

Any ideas? This is on a 201 Phantom.