HUD moving position as health goes down?

[Mazzlefizz]

I don't think I've changed anything recently, but my hud now moves upwards as my health decreases, a couple pixels per health. It's pretty odd. I thought perhaps I had something anchored to one of the new vertical health bars that moves up and down, but I couldn't find anything of that sort.

Has anybody else experienced this? I basically use the noob123 HUD that's included in lots of DART compilations, including Ruin's. Any ideas what could cause something like this?

Here's a screenshot, though it obviously can't capture the moving aspect. You can see the hud in the middle: