For everyone who got a Sony device at MozFest and updated since to a build that changed the update channel to ‘nightly’, there is a new OTA build (aka System Update) out to fix this. Please update your devices as soon as you can and you will be on the latest Foxfooding build. After installing, you can check that you’re on the right build by going to Settings > Device Information > More Information, and verifying that your Update Channel is set to ‘dogfood’.
Note this update might also be available to other foxfooders (i.e. who got their device not at MozFest but elsewhere) who got bumped to the wrong channel at some point in time.
If you have any questions, please post here.