Bluetooth connection drops with Powermeter but not using ANT+

The Edge 840 is dropping my Magene pes 505 Power Meter.  I have firmware 21.19 on the 840.  I tried the same Powermeter with my garmin descent MK2S and no disconnection.

Is it only me ?  

  • Only sorta related, but earlier this year my 840 kept dropping and reconnecting with a PM using ANT+.  I switched to BT and that worked, but I couldn't calibrate the PM from the 840 using BT.  A couple of months later I tried ANT+ and it was working again.  There had been no overt updates to either the 840 or PM during that time, so I have no idea what changed.  FWIW, I prefer ANT+ connections for all sensors.  Only in one other situation do I use BT.