PST occasional quirk

[Elk]

This thread may be of interest:

Is anyone having issues with the new PST getting stuck playing discs?

I have had my PST for about a year, and every now and then, it will meet a disc that it will not play completely through. It gets stuck at a certain point and eventually just stops and the screen/timer goes back to zero. I sent four problematic discs to a friend who has a PST, and he had no issues with those discs. They have been cleaned with the stuff from MOFI and do not appear damaged in any way. Just curious.