I just came across this very same problem today using version 2.5. I'm pretty sure its a bug in the XSD as it conceptually invalidates the response from the 'Query Views For Site' API. Instead of moving the element I would suggest that you copy it instead.
This week we upgraded to 10.3 and now i"m using 2.6 API... still same issue. I'll do a copy instead of a move. I'm having quite a bit of trouble using a new API feature "Refresh Extract Task". Have you used that yet? I'm able to issue the call appropriately, and get a successful response back. I can see the refresh starts on the web dashboard, but then it fails. The only 2 parameters the api call takes are siteId and taskId. I assume I have those correct since I can see the refresh begin in the dashboard. It fails with an error saying a workbook doesn't exist. But that's not a parameter i provide. If I manually refresh the task through the web interface, it works fine. Thinking of contacting Tableau support on this one.