[JFreak]

Well yes and no.

Some plugin vendors do not really code for AAX and AU and VST separately, but instead code once and wrap later. That kind of shortcut may cause troubles fast.

So while common denominiator may seem to be PT, the fact still is even ONE bad plugin may cause trouble in PT and even if not used in a session -- it is perfectly enough that the plugin is loaded into memory.

Troubleshooting would be throwing all plugins to unused folder, then move them back one vendor at a time. Once you hit trouble, you know which one it is. Move it back to unused, continue moving others in and confirm the problems stay away. Then start moving that vendor's plugins in once by one. Same thing, once you hit trouble, you know that plugin caused it. Once you have pinpointed the problematic plugin, contact that vendor and ask for help.

Needless to say plugin versions must match PT version.