I have encountered this issue working on several Sharepoint 2010 publishing sites. If I create a page with a custom Page content type then edit the page properties, the content type automatically changes to the default Sharepoint 'Page' content type. I can manually switch it back to my custom page type but I wanted to try and find a way to prevent the content type from changing in the first place. I always add my custom page content types to the Pages library. Was wondering if anyone else has encountered this issue and if there is a way to prevent the content type from switching when I edit page properties?