Thread:Help talk:Properties and types/Tags inside Property Value

After placing a Reference Tag inside of a Property Value within a SMW Form, I received the following error on the page: "Error: The given value was not understood." Any ideas why cannot be used within a property?

I'm currently running on Medawiki 1.23.2, SMW 2.0, Semantic Forms 2.6, Semantic Internal Objects 0.8.1, Semantic Results Formats 1.9.