Why does a new TeamViewer session place phone call on hold?

hi all,

Generally, when I start a TeamViewer session with a remote user, I am already on a mobile call with that user.

When the TV session connects, my mobile call gets puts on hold - I can resume the call again by hitting "Resume Call" - but this is obviously not ideal to have to do every time!

I'm using a Jabra Evolve2 65 headset connected via Bluetooth to both my mobile and my PC.

Any ideas on what is happening here appreciated!