Yeah, I notice the same thing sometimes. There are some popouts that work really well (Potato Cod in Imax: Under the Sea and Guns in RE: Afterlife), but there have been a number of popouts in other movies that my eyes don't resolve well (read: nauseating) and I miss the effect. I will definitely try the sync invert trick with my projector and see if that helps. The problem seems to happen only with very quick popout moments and when a snow effect, for example, is supposed to spill outside of the screen. Oh, another example that is supposed to be great but didn't really work for me is the vampire deaths in Fright Night.