I found a funky bug that occurs in the WinForms and the NetDiagram component (pre-beta) when you switch between a Bordered Top-To-Bottom Table layout with Rounded Arrows to a Centralized Left-to-right Table layout with Perpendicular-2 Arrows. The Nodes get positioned like you'd expect for a Centralized Left-To-Right layout, but the arrows stay rounded with their control points don't move; only the end points. The results is a loopy, scribbly looking layout.

Try it in the FCDemo.exe. Not that you'd normally switch from one layout to another in the normal course of viewing a diagram, but still, it does seem like a bug.