Strange.. I haven't checked the logcat yet since I am at work.. But I am guessing the FC is being caused by a FaceBeautify plugin because everytime you switch to front cam this plugin gets loaded automatically.. Check if you have this installed and also make sure its the latest version
Edit: Just did a test by uninstalling FaceBeauty plugin and I can reproduce the error you are getting.. There seems to be a bug in the new camera app which requires the facebeauty plugin to be installed for the front camera to work.. Already figured out what's causing this and will fix this in the next update
Thank you for confirming! At least it makes me feel better that I am not alone with the issue and did not spam the thread with useless reports
EDIT: Confirmed, when I have the beautify plugin installed none of the previous issues are present, the cam apps works perfectly.