GroupSessionJournal attachment loading error on Vision Pro

Hi all,

Currently working on a shareplay feature where users pull data from a remote source and are able to share it in a volumetric window with others in the facetime call. However, I am running into an issue where the group activity/session seems to be throwing an error on the recipient of the journal's attachment with the description of notSupported.

As I understand it, we use GroupSessionJournal for larger pieces of data like images (like in the Drawing Together example) and in my case 3d models.

The current flow goes as follows:

1. User will launch the app and fetch a model from remote.
2. User can start a shareplay instance in which the system captures the volumetric window for users to join and see.
3. At this point, only the original user can see the model. The user can press a button to share this model with the other participants using

/// modelData is serialized `Data`
try await journal.add(modelData)

1. In the group session configuration, I already have a task listening for

for await attachments in journal.attachments { 
    for attachment in attachments { ... }
}

1. This task attempts to load data via the following code:

let modelData = try await attachment.load(Data.self) /// this is where the error is thrown: `notSupported`

I expect the attachment.load(Data.self) call to properly deliver the model data, but instead I am receiving this error. I have also attempted to wrap the model data within an enclosing struct that has a name and data property and conform the enclosing struct to Transferable but that continued to throw the notSupported error.

Is there something I'm doing wrong or is this simply a bug in the GroupSessionJournal? Please let me know if more information is required for debugging and resolution.

Thanks!