I had a PT Session start crashing on me in PT11. What happened was just this..
Drumagog loaded in PT10 with Slate Drums as a Plugin. Works fine in PT10 but when Launched in PT11 it works fine when playing the file but when trying to open the GUI of the Slate Plug through Gog, PT11 Crashes! I'm sure its not a Gog problem. What I realized was that the Slate Plugin in PT10 is Rtas and in PT11 its AAX. I'm sure this is where the problem is. Not sure if I can expect a fix for this or not but I just wanted to save others from pulling their hair out like I did last night!