Same problem here but it will resolv by itself may be an other appli like facebook which use constantly the camera and not release it for an other applications.
In fact when i have this problem i can t use the flash as pocket light too. For resolve it i open facebook or whatsapp and try to take a pics with front and rear camera and it release the front camera and video in the photo application. After when i use this last application i change the flash setting and it release that i could use use as pocket light... A simple workaround that i use for a month . Since 4 days no other problem apparently so may be it s due to an application that received a bad update and a new one which correcting this problem.
