Issue with XLIFF sync and group id

[NutmegAdam]

I have a Blazor Server project, with a Resources folder, and a resx file per page, like this:

ProjectName
    Resources
        Pages.Index.resx
        Pages.Index.es.resx
        Pages.Lobby.resx
        Pages.Lobby.es.resx
    MultilingualResources
        <ProjectName>.es.xlf

The MultiLingualResources folder, and the xlf file in it, were generated by ResXResourceManager.

When I edit a neutral resource that belongs to Pages.Index.resx, the xlf file is populated with the keys and the neutral text for all keys in Pages.Index.resx, as expected. But if I then edit a neutral resource that belongs to Pages.Lobby.resx, the xlf file is populated only with the keys and the neutral text for all keys in Pages.Lobby.resx, and the Pages.Index keys are gone.

Looking at the xlf file itself, there seems to always be only one node, where the id matches the project name and path to the resx file. It looks as if there should be a node for each resx file, but only one is ever written. As such, it looks like a bug where not all resx files are entered into the xlf file.

My apologies if I have misunderstood the expected behavior!