[BLOCKING] Playsound playback does not stay on player

Verification builds: Minecraft - Publish_457077
Summary:
The playback sound behavior between 1.1.X and 1.2 has changed, we are unable to get the sound to stay on the player when moving.

Impact: Unable to play sound on player for story purposes.
The player is always moving, this means the sound will disappear when the player is moving away from the playback positions.

Repro Steps:
1) Load Blozark gamescom demo in minecraft 1.1.X
2) Run the command

playsound aira_s1_1 @a

3) Run away
4) Load Blozark gamescom demo in minecraft 1.2
2) Run the command

playsound aira_s1_1 @a

3) Run away

Observed Results:
Sound Playback does not stay on player when the player moves.

Expected Results:
Sound Playback stays on player when the player moves.

Screenshots/Videos attached: Yes
We tried repoducting this with a standalone mcpack, but was unable to do so.
We can provide you with the mcworld of the Blozark Gamescom demo. (Message @mewulf on slack)

Notes:

In the sound_definitions.json file you can add the value "stream": true so the playback stays on the player even when moving, we think this is the correct way of telling Minecraft the sound should stay on the player when moving.

But we observed this this is not the case, in Blozark (1.1.X) we thought we used this to achieve this affect but we seems to have done something else to get the effect without the "stream": true and are confused why its broken in 1.2.

In this https://www.youtube.com/watch?v=eWeMswGTkPA video you can see the test in 1.2 but this effect is the same in 1.1.X.

tldr; We are confused on why it works in 1.1.X and not in 1.2.