@stropbu
Just quit tested on my N5 and i can confirm i have issues with its camera.
No all quite the same as you but there are.
I have the rear camera working (preview and photos taken), but once, after manual focusing on a very bright part of my tv screen, app control just vanished.
On front camera, preview is reverted, but photo that outputs is in right orientation (edit : just tested on my MX4, same behavior on front camera, maybe it's intended ?)
Also i have what you describes, manual focusing with front camera just make buttons not working for some loooong seconds after focusing finished (capture button color stays gray instead of white during that time).
Did not tested in OTA-23 and previous as it is my spare phone.