Camera app collapses
It happens randomly. I noticed since last OTA (22). . Camera app collapses but the icon on the dash it shows as it were still opened (explanation: There aren't any window open for camera app in the multitask but the icon on the dash shows it at still opened). When this happens you can't open the app through drawer or through dash.
There are two ways to solve the problem: long click on the camera app icon on the dash and select "exit" or reboot the phone.
Attached is the log of the app when it collapses but I don't know if it have something useful.application-click-com.ubuntu.camera_camera_3.2.3.log