I've noticed this over several days and I kept waiting for it to fix itself but it has not done so yet. When you hover over someone's username, in the bubble that comes up, their username, status, and trophies overlap the HA.

On pet pages if you hover over your own username, the avatar seems to be smaller to accommodate for all this information moving to the left like this.

Firefox 39 on windows 7.

edit: It's not my custom css because it persists when removed.

This just started happening to me now too, weird. I did notice it on pet pages for a couple days now.

I'm using Firefox 39 on Windows 8.1