Wandering piano rolls sometimes occur with rolls that have been
"off punched", meaning the roll is tracking properly but the holes
don't quite line up with the holes on the tracker bar.   Old rolls
sometimes contract as the paper ages and dries out which can also
contribute to tracking problems.

Most common cause, however, is a problem with the tracking mechanism
itself and this should be checked and, if need be, corrected.  A roll
that doesn't track properly when playing will wander on rewind.

In the meantime, the roll should be rewound slowly, guiding it
manually if necessary, to avoid damage.

Peter Vander Veld