Sound behaviour inconsistent

Partner Team Reporting: 
Noxcrew

Partner Rank: 
1

Verification builds: Minecraft - Release_3547235 1.14.1.4_rc1

Summary:

When a sound is set to the category of 'UI' in the sound_definitions, the sound should play on a player and carry full volume wherever they move. (This is an observed behaviour from developing in Bedrock for a while now. As far as I'm aware, there is no documentation on this).

However, sometimes (and we don't know why), the sound will fade out if you move around, and sometimes it will remain at full volume. A relog will usually (and randomly) switch between the two behaviours.

Impact: This is causing unexpected behaviour with sound like music and dialogue (ones that should follow the player at full volume at all times) and breaking player experience.

Repro Steps:

1. Download the attached world
2. Load up the world and walk in the direction of the 'Boo!' sign until you find some command blocks on your left (We've purposefully placed these away from the spawn chunk due to some strangeness we've found here too)
3. Hit the button on the middle command block.
4. Observe sound behaviour by walking away from the command block.
5. Reload the world
6. Keep repeating step 3 to 5 until you find a change in the sound's behaviour (This can sometimes take quite a few reloads - it's likely you'll reproduce it faster with more people trying it)

Observed Results: The sound fades as you are moving, more often than not, but sometimes works as intended (doesn't fade)

Expected Results: The sound is always at full volume, when moving around (as it's set to UI)

Screenshots/Videos attached: Yes

Notes:

In the video, we're on a server, relogging constantly to try reproduce the bug. At the start of the video, the sound is playing at full volume, even when the player moves.
The player then relogs into the server, plays the same command block and now the sound is suddenly fading away as they move (And nothing has been changed at all).

Here is the sound_definitions.json entry of the sound that we're testing: 

"beepmono_ui": {         "category": "ui",         "sounds": [             "sounds/beepmono"         ]     },

The command block uses the command: playsound beepmono_ui @a

The sound is a 10 second clip of a repeating beeping tone

We've tested this in singleplayer as well, and it's reproduceable. We haven't been able to find a reason to why it happens, it's random. Sometimes it'll take quite a few relogs before you notice the change.

Bug on server: https://youtu.be/2GsxaXpkndo
Bug on singleplayer: https://youtu.be/5508stSyneY