Music buffering and dropped out + Optical HRM armband

Update: I further test without Polar Optical HRM connected,  only Sony WF-800N , when music playing alone , it works flawlessly.

However, at main screen I.e. watch face, after pressing the top right button into workout page, try treadmill run and run, before I start run , music starts to drop out every 5 seconds . 

Software 16.8

ANT/BLE/BT : 6.11

Try downgrading the ANT/BLE firmware to v5.04.  Make sure you turn off auto-updates when you do it or both Express and Connect will put 6.11 back.  I have had all manner of drop-out problems with 6.11 but 5.04 works flawlessly for me.  Why Garmin hasn't been able to figure out what the blankety-blank they broke between those two and take care of it is beyond me.

Thanks tickerguy May I know how to downgrade ANT/BLE firmware alone to v5.04?  Is firmware 16.8 maintained or which firmware offer ANT/BLE v5.04? 

You need to have (or find) one of the old beta releases for the 6x; it's in there.  I keep backups of the system on which I download beta firmware around and was able to grab it out of there, thus I have it.  It's only suitable for the 6x (and I assume not for APAC region devices as they repeatedly warn);

Thanks for the tips, I just bought this F6 Sapphire two weeks ago. I will keep in mind to download and backup various versions of firmware from now on.

Anyone having old beta firmwaare release for Fenix 6 with ANT/BLE/BT v5.04,?

My F6 Sapphire have upgraded from firmware 16.8 to 16.9, having the similar ANT/BLE/BT v 6.11, same buffering and dropped out issue when I start an activity.

Hi all, want to ask the latest F6 firmware if bluetooth issue resolved?  Previously I downgrade to ANT/BLE v5.04 in orrder for my wireless earbud to pair with F6 Pro.  I plan to upgrade F6 firmware and worry the bluetooth issue.  Appreciate if someone has tested can share your feedback.

It's not terribly helpful to you maybe but for the record the WF-SP800N do this on mine too (F5+ and F6) but the WF1000xm4 do not and neither do the wf-sp700n. The  WF-SP900 have the issue too, but they have MP3 built in anyway. The WF-1000XM3 also suffer from the issue.

I have all these headphones and have tested on various firmwares and it's pretty consistent but definitely a watch issue as the breaking up only starts when you start an activity, all of the headphones work fine if you just sit in the Spotify app and don't start an activity.

Thanks for your reply.  I am using my old Jabra Elite 65t active replace my SP800N , thanks for reporting XF-1000XM4 is working well with Fenix 6, that's I am looking for ... but it does not have NFC easy initiate Bluetooth pairing unlike previous 1000XM3, right ?

Will try to update my latest Fenix firmware since I have disabled update due to Bluetooth issue..