I just noticed something while playing deGroot as demoman:
http://steamcommunity.com/sharedfiles/filedetails/?id=677843694
No, it's not the "invisible ammo/health/bar bug, it's that the bar blends in with the demomans sleeve.

It would be nice if you could do something about that, perhaps make it a darker/different color or just move it or make it bigger

Edit: This bug may not appear whilst playing with a different FOV/Screen, just thought I'd point out