Edit's 'Save' button was 'Vote Now'
 

Just now, I edited a post to add a link.

Instead of a Save button in its usual place, I had 'Vote Now' instead. Of course it was a save button, mislabeled. ;)

Maybe I just haven't seen the bug before because I'm on Safari on a new Mac?

I think it may well be a browser issue. Check it on a MacBook Air :)

i also see this fairly regularly, but going into advanced fixes it.