Chaps, its acting weird because the part is (somehow) corrupted. When AD goes screwey also use the 'check part' function!!!
As you can see there's a problem with a face and that will have a knock on effect. What's causing the corruption? I can't say, haven't looked at the part beyond seeing why the OP was seeing what he was seeing (excuse the grammar, its been a long day and I'm knackered). If I find something I will post it here. Bottom line: use the 'check part' function, it's really useful.