I have a OnePlus Two, flashed with Cyanogen Mod 12.1 nightly. I can use the camera, front or back, no problem in the actual camera app.
If I use a program that wants to open my camera (i.e. Google translate, Google authenticator, barcode scanner, etc), my phone goes so slow, that I need to reboot it by holding the power button until it comes back on. If I don't do it quickly, my phone starts getting very hot in my hand. This does not happen with the default camera app (com.android.camera2).
Is there a possible setting that I can change to make it work properly? I like the phone otherwise, but I may go back to the One, if this can't be resolved.