I've had four handsets with this problem, sent the latest one back today. I haven't posted on here for a while as wanted to try and find a handset without any issues and really give the phone a chance to sway my decision from my previous posts. Unfortunately, I have given up purely on build quality issues. I actually managed to get over missing/poor app frustrations and really enjoyed using the Update 1 firmware, folders and Cortana etc.
During my frustrations with my first and second 930 I purchased the Galaxy S5 LTE-A version from Korea and I have to say it really is a stonking phone, god knows why Samsung didn't release this as the actual S5 handset, dropped the ball big time with that decision.
Anyhow, back to the Lumia 930. I don't think that it's acceptable to have four handsets with build issues, especially on whats meant to be a flagship device. I have never, in 20 years of having mobile phones, had to send back a handset four times. In fact, over the past 5 years, the only phone I returned on build quality was the first HTC One M8 I received, as the finish around the sim and sd card release holes was unfinished and sharp. In comparison, that is minor, the screen bonding agent failing because the phone gets too hot is a very major concern. For me, I couldn't live with it, as I kept thinking about what it will be like in 6 months time!
I will return to Windows phone when the next Lumia flagship device becomes available, as I really do love the design, OS and camera, but they had better up the quality of the handset by then.