I have a Lumia 920, currently on the developer preview. It is now on Cyan, but the display has developed a tearing artifact - much like the tearing you get on PC's when the refresh rate isn't syncrhosized.
There is a video on youtube displaying this issue :
The proposed solution is to use the recovery tool, which I believe is an unacceptable solution. Coupled with this, the phone now feels very slow, and I'm not sure if it's due to the "sync" issue, or unrelated.
My OS version is 8.10.14176.243
Firmware : 3051.50009.1424.0008
H/W revision : 184.108.40.206
Let me know if you need more information.