There's a limitation in the product with creating circumstance definitions that involve properties on an embedded page.
You can disregard this warning. It's a relatively minor performance issue, and won't affect the overall functionality of the app. The circumstance definition saves, and the application will apply the circumstancing correctly.
The warning doesn't occur if the property is written on pyWorkPage, rather than a page embedded on pyWorkPage (such as .Employee.MaritalStatus).