I got my 507 update on December 18, 2017 and now I lose the Bluetooth Icon under settings almost every day. The only temporary fix is to restart the Hopper3 box. This fix isn't very practical if you have programs recording in the background.
I had this problem earlier with U336 and U341. It had been fixed now its back.
Strangely I keep the Bluetooth Icon on my 4K Joey where I didn't need it.