Just got the Nexus 4 last week and had the Fido staff install the protector. Notice that when I answer a call and the screen goes black, the screen wasn't turning back on after until the call gets cut off or hangs up. Found out that it was because the screen protector was causing the issue, cutting off the piece that covers the sensor (upper left corner of the phone, the 2 dots), fixes the issue.
just an FYI to those who might come across it and thinks that there is something wrong with the phone. :catwink:
** Edited to add labels **