GROUPING Tag not populating for M4A (MP4) files

Issue description:

I’ve been unable to get GROUPING tags to show for M4A files

I’ve tested GROUPING as well as CONTENTGROUP

Logs:

Upload description: GROUPING_TEST

Additional information:

 
I’ve included my test file under the same description as my logs.

Not sure if this is a mistake on my end, limitation of MP4 container or a Symfonium thing.
 

Reproduction steps:

 
Using MP3 tag I added a GROUPING tag to my MP4 (M4A) file & attempted to re-sync my library

Sync was successful but there remained no GROUPING tags visible.

I attempted this again using CONTENTGROUP, same result

Another attempt using both, same result.

I also tried clearing my tag cache & then running the sync but the results were the same unfortunately.
 

Media provider:

Local device

Screenshots:

     

Works fine in beta 2.

Oh nice

I do not have beta 2 just yet. I’ll update tomorrow & see.

Thank you