Hi Justin,
I had a ball group that collides with actor group, spikes group & tiles group (All custom groups I created). I created another superBall group and wanted it to collide with spikes group & tiles group alone.
The ball group collision was already set to actor, spikes & tiles. When I pressed 'create new' to create a new group all collision set for ball group changed randomly... Its collision to actor was turned off automatically.
I didn't give it much thought at the beginning as the groups had only few collision that I remembered and recreated. But this kept happening everytime I created a new group. Everytime I create a new collision group, the collision group for some other or all other groups modified automatically and randomly...
Hope I've explained better. Just try to create many groups & test everytime you create a new group. May be this error pops up only in windows 7? I just have no clue. But I'm sure that it's a bug as I did nothing else while the error appeared.