Sorry, me again!
Your otherwise excellent plugin seems to have a bug ... or maybe it's just me.
WP version: 3.5.1; CCTM version: 0.9.6.7; Theme: Montezuma (Bytesforall) 1.1.3
When 'bulk' editing posts in the "Dashboard | All Posts" screen, when you use the categories filter, then try to 'bulk edit' posts, you get an "Invalid post type" error message (in the usual WordPress error screen format).
Through a process of elimination, I've confirmed it only happens when the CCTM plugin is activated. I also tried switching to the 'default' Twenty Twelve theme, to eliminate a conflict there, and the error message still happens.
If you need any more information to try to track it down, please don't hesitate to ask. :-)