Facebook volume anomaly

I have the latest unitilite.

When I listen to Spotify free through Bluetooth input using my iPad air 2 the volume is perfect. However, if I am browsing through Facebook at the same time and watch a posted video, which subsequently overides spotify playing through the the unitilite, when I go back to spotify the volume is at one third of what it was even though it is indicated on the unitilite at the same level. The volume on the iPad is also the same and hasn't dropped down either. It is a marked reduction in volume output.

The only fix is to press a different input on the unitilite, come out of Spotify and then back in and then back into Bluetooth input on the Unitilite. All is then restored. Anyone else noticed this?