I just got an update notification, and I noticed the green update icon isn't properly clipped or sized -- there's a little bit of another arrow visible on the right edge. (I'm not sure if this is because this icon comes from a sprite sheet & we're failing to clip, or if it's a background-image and it's getting tiled, or something else) See attached screenshot. I'm currently running yesterday's Nightly, 43.0a1 (2015-08-25) -- that's the build that I received this update notification in.

More info: I'm using Ubuntu 15.04, with 64-bit Firefox Nightly, on a Dell tower with 2 24-inch Dell monitors. (Not a HiDPI screen or anything like that.) I haven't tested with a fresh profile, because I don't know how to easily trigger an update notification with a fresh profile. This is the first time I've noticed this issue, so I suspect it's a regression, though I'm not sure.