Headphone disconnects after starting activity

Hy!

Since 10.10 FW I've a weird issue with my previously flawlessly working headphone (Jaybird Vista).

When I go running usally I start listening Spotify before leaving my apartment, then I go downstairs and start running activity in the street. After a few minutes of running my headphone says "Not connected" and the watch shows me a PLAY button instead of PAUSE, so the playback has been paused and the headphone has been disconnected. When I press play and choose Jaybird Vista, it connects and starts to play, but disconnects after another few minutes, and so on....

If I pause my activity and restart the watch then continue my activity and start Spotify again it works till the end without and disconnect or dropout... however the language of the voice prompts are changing from hungarian to english.

If I keep my headphones off when I start running, and only start listening to music after started the activity the connection is fine and I've zero disconnects during the workout, however the language still changes from hungarian to english.

What I've tried:

  • repairing my headphones
  • tried the headphones with smartphone, no dropouts or disconnect for hours
  • change the default voice language from hungarian to english
  • made a full factory reset with secondary master reset and even Garmin Connect reinstalled and repaired
  • installed 10.75 beta

Current software:

  • Fenix 6X Sapphire
  • FW 10.75
  • GPS: 4.50
  • Wi-Fi: 2.60
  • CIQ: 3.2.0
  • BMX: 0.9.2
  • WHR: 0.09.02
  • ANT/BLE/BT: 6.06
  • Sensor HUB: 7.12

None of these solved the problem, so now I'm a bit clouless.
Everything was working fine with 9.XX firmware, so it must be something software releated, but I'm out of ideas.

Thanks for your answers!