The Task.Create operation fails displaying the layout in the UI.
How to reproduce:
1. Create a chain that uses Task.Create
2. Basically, first use Context.SetVar and set a variable named, for example, assignee to just "user:Administrator. Then call Task.Create and use this variable name for the "variable name for actors prefixed ids" field to "assignee"
3. In Designer, bind this chain to a button (displayed in Document Actions, no filter)
Deploy and test: Upload a document, click your button => the task is assigned, but you can't handle it. (see screencast Task.Create-no-valid-layout-720.mp4 )