video playback breaks bluetooth speaker connection.

Hi,

Problem:

When I have my Bluetooth speakers connected to my MacBook Air playing sound ( from iTunes or the browser ( youtube ) and then either open a video in QuickTime or enter preview mode ( through tabbing spacebar or when the finder window shows it ) the speaker will stop playing sounds from iTunes or the browser once the video in QuickTime is done.

I then have to disconnect the speakers Bluetooth connection and then reconnect for it to play again. If I then open or preview a video I will have to do the same again.

Setup:

• MacBook Air, Early 2015
• High Sierra V. 10.13.4
• The issue occurs with both UE Roll speaker and Sonos speakers.

What I've tried:

• Updating macOS
• updating drivers/software for speakers.

The issue only seems to occur with QuickTime and finder preview and causes no issue with other video players or editors ( i.e. adobe after effect and premiere )

I don't know what else to try so any suggestions would be grand.

Thank you in advance.