I have had the problem with every set I have had. I did find out though, if you run less apps and keep removing past recordings, it runs a little bit cooler.
LOL, mine actually got up to 125 degrees F once! I had to pull it off my head before I could get burned.... the metal band seems to keep the heat and just makes it worse.
I have to limit my videos to about 5-10 minutes, then download to a laptop and let it cool for about 20 minutes, makes a 2 hour project last all day......but hey... I decided to get a glass instead of a go-pro.