HRM RUN not found when start a new run activity after a previous run activity with HRM Run and bluetooth headphone

Hi,

Watch : Fenix 5plus Saphire.Firmware 9.00. But was the same with previous FW Versions.

I start a run activity, connecting my HRM RUN, STRYD and a bluetooth headset and hear music via Amazon music during the run.

Next day when I start a run activity my HRM RUN ist not found by the watch. I have to reboot the watch and the HRM is directly connected.

This happens only when I heard music via headset. 

Any ideas how to fix it ?

Regards


Richard