Can you see if adding the OldGuids parameter to the options record resolves this.
OldGuids : A logical (true/false) that sets whether char(36) columns (if false) or binary(16) columns (if true) will be treated as GUIDs. The default value is false.
Otherwise you should (have a Power BI administrator with in your tennant) create a support ticket in the Power BI admin portal so Microsoft can look into it.