Why do gliders suddenly become pouch protective?

The only experience I have with that is when we got a new 4 month old female. She came in a pouch and that was it, and she was extremely aggressive if you touched, jossled, or reached towards her pouch. I assume because it was her only safe spot and she had no idea who we were and she was scared. It slowly went away over a month as she got comfortable with us, and now she's fine with pouches. She prefers to sleep in tunnels a lot of the time, though. If you don't already have tunnels, you can try adding some into the cage and it might help. "Open" pouch-like things are better for pouch aggressive gliders if it's a problem for you or they're aggressive towards cage mates.

Is this a glider you've had for a while, that's just became pouch protective? Or is it a fairly new glider?

What exactly are the actions of your glider? Is it toward you, or other gliders?

Are other behaviors as usual, or do you notice differences in activity, appetite, and potty?

Hello!
It was Guenevere yesterday, one of my original four whom I have had since October 2012.
She was in the giant pouch I got a week or so ago (they LOVE LOVE LOVE the huge pouch!) and the other gliders were waking up, going about their grooming and eating. Gimli (her bro) was by the top of the pouch and she was leaping out repeatedly and crabbing. I thought it was Thor because he does that on occasion...but to my surprise it was Guenevere! Activites, appetite, and potty all seem usual. BTW Thor only started doing that a few months ago (before we got Luna). Even if he does that after some persistence the other gliders are usually able to get in and snuggle with him anyway. He sleeps with his colony about 90%-95% of the time, only once in a while by himself. Since we got the awesome giant pouch they have all been in it every day, even ignoring the nesting box which was their previous favorite. It's actually kind of funny to watch because it's like a grumpy Jack-in-the-Box and the other gliders look completely perplexed.
Maybe she just loves that darn pouch...