Huh, very interesting!
Sometimes when I'm shooting basketball hoops, my shot will be off-center but inside the hoop. If it catches the rim just right (just wrong?), I can see several rotations around the inside of the rim before the ball finally falls through or gets spit back out. Several times I could have sworn that the center of gravity of the basketball was below the plane of the rim before it got shot back out, and maybe this video shows an explanation of why that can happen. It will still be frustrating to miss like that, but at least now I'll know why...