Speaker setup as keyboard
Don't know if this will fix the issue for you, but for some magical reason, it worked for me. 
I removed the speaker from the list of Bluetooth devices that were paired and was ready to start again when I decided to just listen to music through the internal speaker. Pressed play and got the sound coming from Bluetooth box. It doesn't show in the Sound settings (it says Internal Speakers are being used) and it's not on the Bluetooth panel, although the bluetooth is showing a connection. Hope it works for you, although given the nature of this fix, don't be surprised if it doesn't.

BTW, I'm using a mini Smart Box II speaker on a MacBook Pro with Sierra 10.12.6.