Garmin Fenix 6 Volume Controls not working

Me too 

Testing with Jaybird tarah pro

v4.20
Sensor Hub 2.50
ANT/BLE/BT 3.60

First Test

1. When first received 4.20 last night.  I started off from a point in which there were zero BT headphone 'saved' in the watch. I had two (the tarah's and a 2nd off-name brand), but I removed them.  
2. I started the music player and it asked to locate BT headphones. I turned on my Tarah's but they paired with my mobile phone next to me. so I disabled BT on my phone, and then powered off the tarah.  I restarted the scan on the F6x and powered on the Tarah into pairing mode. 
3. they connected, and I was able to raise and lower the volume both on the watch and the tarah's
4. when I was raising and lowering the volume the meter bar on the watch was going up and down.  This was true when changing volume from watch and from tarah.  Only different is when using tarah the volume meter was grey rather than black.

Second Test (this morning while I was already out running)

1. about 2 miles into a 4 mile run (I should note the RD pod did connect and was working) I turned on the music app
2. the watch didnt appear to connect to the tarah's, so I went into the sensor menu (again while run activity was ongoing) and i removed the Tarahs
3. back into the sensor menu I added new BT headphones, and  and power down then up the tarahs.  I wasn fast enough so the watch asked me to retry.  I did. 
4. tarah's were not in pairing mode so they didnt connect (duh of course not).  power tarah down again, powered up into pairing mode, and had to hit retry on the watch again.  They connected.
5. music was not playing, but like many observe, sometime while connected, it seems you need to skip to the next song, and then it all work.  this was true for me.
6. tired volume up/down on the tarah.  it worked.

Third test (just now)

1. Tarah pro are within the sensors, but I have it set to Off.  Tarah were also powered off (see photo with status as off)
2. started the music app, received Connect Headphone to Start listing "connect now" or "connect later" option (see photo)
3. powered on the tarah pro's, then I selected the "Connect Now" option
4. received message "Searching for headphones"   Not unexpected, but might have been nice if the watch was smart enough to switch my tarah pros sensor status from off to on.  (see photo)
5. backed out to root menu, then into sensor menu to change tara pro sensor status to on
6. watch briefly said connecting, then switch to connected, and music started to play (see connected photo)
7. music was playing (photo)
8. tried watch volume up/down  it worked (see photo with black volume meter mostly empty then mostly full)
9. tried tarah pro volume up/down.  it work (see photos with grey volume meter, one short one long)
10. lastly. when I entered into the watch volume controls (with the +/-) I also tried tara volume control  it works.
    

Four test (just now)

1. music still playing from last test.  I powered off the tara pros  (music player reported 4:28 into the song)
2. powered off the Fenix 6x Pro
3. powered on the Fenix 6x Pro (BT headphones still powered off)
4. entered into the music app.  It showed same song, also 4:28.  I hit play (BT headphones still powered off)
5. Connecting to Jaybird Tarah P  (of course it fails, they are off).  watch puts me back into music play like in step 4
6. power on the tara
7. I was about to hit play.. but I watch connected automatically and started to play.

I have no doubt that others are still having trouble.  So far, i'm not.  I think the sensor hub is still flaky.  I think tarah pro (maybe other BT headphones also) has something in its internal profile to 'remember' a couple of devices it connects to.  I wonder if this complicates things on the watch.   My only suggest for those having some difficulties would be to try to remove all the BT headphones from the sensors.  power off/on the watch.  Using the sensor menu, add new BT headphones.  Then enter the music app.

Also for Jaybird tara pro users. I almost NEVER use the jaybird app, but I did last week. There was a firmware update for them.  Not sure how old it was, but that potentially is a difference as well. Try the Jaybird app to see if you have firmware update for the tara pro's

good luck.. hope the above helps some folks

Still not working for me, Fenix 6s, version 4.20 , Anbes TWS Headphone

6x Pro and airpods. Had the same issue. Problem still there after recieved 4.20 update OTA. 

Fix: Removed connection to airpods then restarted phone and reconneced airpods. Now it works.

As for the suggestion the problem only occured with headphones without internal volume control, I say no. Had same issue earlier with Sennheiser momentum 2.

Hope issue solved now.