LocusMap, Bluetooth, Heartrate, failure

[Joska]

Hello, and first of all, this ist a Google Translation, so I bag your pardon for all nonsens I could have written....

For 4 weeks, I have replaced my SonyZ5c by a (for my eye much better readable) Sony XZ2 / supplemented. I used the Z5c for all activities, mostly tracking my running tracks. If I also wanted to measure my heart rate, I once connected the existing chest strap (Berry King) in Locusmap. After that, after a run, I was able to release the strap, finish Locusmap and on the next run it was enough to put the strap back on and the connection between Locusmap and the strap was automatically built up when starting a running record.
Now the difference to the XZ2: The initial description until the end of the first run recording is identical. After completion of all recordings and a new start a few days later Locusmap does not find a Bluetooth device for recording, the small slide switch for the BT 4.0 belt is disabled.
Now I have to delete the assignment in the Bluetooth Manager, then locusmap immediately finds the chest strap again and the activity can start.
Does anyone know this little problem, and has a hint on how I can restore the state that worked well with the Z5c.
Greetings, Joska: D