I recently bought my first Isis. The Titanium version from marbles in USA.
I think I've had it to the halfway point a few times though I can't be sure. The plunger has solidly stopped short, but there is definitely something larger than the other two bearings moving around in there.
I hear the bearings making a light *swish, swish* sound in the puzzle but there is also a heaver *clack-clack* sound when I shake it. I've read that some puzzles have had a key inside in the past that caused some issues. I'm worried something may have come loose and is causing problems.
Any help would be appreciated.