Can’t see Bluetooth devices for playback, iOS

Hi,
I have seen a related problem, that seems to indicate a possible bluetooth issue with Cubasis. The problem is easy to reproduce for me.
I run an IPad Pro 9,7 128Gb with IOS 11.3 and the latest Cubasis.

Problem :
My bluetooth speaker Harman Kardon Esquire switches from normal Bluetooth mode
(Blue Led on) to phone mode (Green Led on) which means inferior sound, with no bass
if Cubasis is started (in background mode) and if Bluetooth is Off in Cubasis Settings/Audio.

The only way to get the speaker to work in normal Bluetooth mode with an app like Spotify for example and give normal full sound is to do one of these two things :
A: Shutdown Cubasis completely
or
B: If Cubasis is started, Cubasis Setup/Audio: ”Bluetooth” button must be
activated/selected.
I do not understand why this setting should affect the function of the speaker when used
with another app like Spotify.

Could it be that Cubasis is polling for bluetooth peripherals like keyboards etc and happens to confuse the bluetooth speaker making it change to some phone mode or something like that ?
(This is just a wild guess since I have not had time to investigate further.)

I hope Steinberg could comment on whether this could be an issue with Cubasis
possibly.
Keep up the great work !

/Jeepster