I am another Android user with problems. Worked OK'ish with an 8gb Kingston card so I purchased a Samsung EVO 128gb MicroSDXC from Amazon and to make doubly sure it was genuine, I checked it with H2estw, which found all was OK. Formatted in the camera with FAT 32 but afterward's the camera is reporting the card is 95.73% full. However I read the following from above... 'With the latest firmware, the SD card will be formated automatically and fill the SD card up, but new video will start cycle recording again'. So I guess that answers that one, but it was not automatic, I had to format manually. Anyways, its working again but I have not yet had a long run to see if it overwrites and uses the whole 128gb card.
There is an option in the app to format the card if that is needed, but I suggest you try to downgrade to 3.3.1.6 if at all possible.