Rear glass not folding correctly

[Todd Mac]

I have a 2004 Boxster S and just before winter I would put the top down and a few times it wouldn't close properly. As best I can tell the glass window is not sliding back far enough when going down and it stops the process from completing because it is wedged. Any idea why the top wouldn't fold correctly?

While parked I keep the top up - even in the garage (2 1.2 yrs) - but I don't think the original owner did. To get the top top work correctly I have had to start the close process and then adjust the rear window by pulling it up and back from the rear and that allows me to push the top down and forward the little bit it needs to go.

I would say it's probably getting caught up in the top of the fabric but there is no reason for that to have started now that I can think of. Has anyone had the same issue?