I was able to save a front camera picture for the first time today.
Trying to switch to the back camera does nothing; whatever the front camera was seeing remains frozen in view. If I close the app and then come back to it, I can tell that the back camera is engaged, because the “Focus” control has been added to the screen. The view is just pitch black, though.
One curious thing: there’s a delay in viewing the subject through the front camera, e.g. the subject moves a bit and the same action is seen a second or two later on the screen view.
It also seems that I have to crank the phone’s brightness all the way up to see the subject, and again, only present with the front camera. Back camera view sees nothing.