Roles with Power BI embedded

Hello all, I'm a new member and first time poster on this forum.

I am creating a internationalized embedded Power BI report and as part of this I will be using one role for each language that act like this

EnglishRole: [Language] = "English"

SwedishRole: [Language] = "Swedish"

The problem is that when embedding, we already use a role for RLS.  When adding one of these new roles none of them work.

The C# code for creating the embed token has this:

var identities = new List<EffectiveIdentity>
{
    new EffectiveIdentity
        {
            Username = siteId.ToString(),
            Roles = new List<string> { "CurrentSite", "SwedishRole" },
            Datasets = new List<string> { report.DatasetId }
        }
};

What I've added is the hardcoded "SwedishRole" to the Roles list for testing purpose. After doing that, it doesn't work plus CurrentSite role also stops working with this change.

I have tried putting information in the CustomData element but that was always blank when I wanted to use it in the embedded Power BI report so I have to solve it using one role per language.

Is this a bug or am I using roles the wrong way?

Edit:

Accoring to the docs this should be possible https://docs.microsoft.com/en-us/power-bi/developer/embedded-row-level-security