We have an access door to our attic in the master bedroom closet. We found the panel lifted at an angle about 2 inches. It is far to high for our children to reach, and neither my husband or I pushed on it from below. I was wondering if the air in the attic could suck the panel door up? When my husband looked in the attic, the insulation was untouched and everything seemed to be fine. It is a mystery to us why the door would be lifted.
Can anyone help us with this?

If the paneling is thin enough and there is a draft in the attic then it is possible

Yes, this is quite possible to happen. If you don't want this to happen in the future would suggest that you install some sort of latching device no matter how simple to prevent the hatch from coming open. Even something as simple as a hook and eye system would work and be easily opened.

A strong gust of wind passing your roof line can cause a slight vacuum inside your attic and suck on that lid. It is the same air flow principal that makes and airplane wing fly.