QueryAsync throws if stored procedure selects no column

I am experiencing an issue where connection.QueryAsync("SP_Test") throws an error when my SP_Test looks like this:

IF NOT EXISTS (@Id = @RetrievedId)
BEGIN
    RETURN 3; -- Not allowed
END

SELECT
      [Id]
    , [Name]
FROM
    Users

RETURN 1; -- Successful

This is what my whole C# code looks like:

var parameters = new DynamicParameters();
parameters.Add("@Id", id);
parameters.Add("@RetVal", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);

var dbResult = await connection.ExecuteAsync("SP_Test", param: parameters, commandType: CommandType.StoredProcedure);

// See if not allowed.
if (parameters.Get<int>("@RetVal") == 3)
{
    return "not allowed";
}
if (parameters.Get<int>("@RetVal") == 1)
{
    return "this is ok";
}
            
//...

There is no problem at all when my SP returns no data (with column selection) or using connection.Query instead but when I don't select anything and return instead, QueryAsync just throws. No matter if I use strongly-typed or anonymous.

Should not dbResult have been null instead?

Reproduce the SP_Test stored procedure with QueryAsync, ExecuteAsync, and Query, using the shown return-value parameters. Start at the QueryAsync entry point and trace how a stored procedure result with no selected columns is handled; done means the no-column case has defined, non-throwing behavior consistent with the intended result.