Is it possible to use the GlobalID as the bind for a subreport?

I have a master report that has a subReport to pull in some of the information from a related Attachments table.

I can preview the subreport by entering a GlobalID variable and the results appear. When I try to bind the master report to the subreport using the GlobalID value it fails and the report will not generate.

This is the error I am seeing in the console:

Error: 0: Unexpected Error: System.Exception: Object must implement IConvertible. ---> System.Exception: Object must implement IConvertible. ---> System.InvalidCastException: Object must implement IConvertible.

Has anyone successfully used GlobalID as the binding variable to a subreport in Reporting5?