Share your experience!
Does your phone has a protective film or glass and/or cover?
settings > apps > all > camera > clear data > restart the phone > check again.
I've seen others with similar issues because of a glass cover, how to test it
settings > about phone > diagnostics > test > test the screen
first with the glass then you can remove it and check again
I have a Xperia Z5 Premium and I have a protective film and I don't experience this issue, don't take me out of context, the first thing is to try to figure out whats causing the issue and then its find a solution.
Keep us updated, just wondering does the protective glass cover the proximity sensor?