The famous or not so famous Grado wobble

I currently have a Grado Reference sonta (super sound) cartridge.....and after about 300 has developed a wobble or shutter while on the record.....and not ALL records?? This has happened before (a long time ago) and I was wondering if any of you hve experience the same? What did you do to fix it?? I, at one time, even had Joe Grado himself look at the set up and he could not find a cure....could it be put cartridge set up? poor arm (doubt it) ?????? Any help????
P.S. I have a Linn Sondeck with Itoch arm on a very light table (could this be the problem?) on wooden floors.

An LP-12 on a light wooden table on a wood floor is a formula for wobble. A wall shelf is the best alternative, preferably on an outside wall. While the suspension on the Linn is very good, the system is suseptible to vibration in ways a VPI, Walker or Basis are not.

the grado DANCE is what ive heard it called. using a grace 707 and a $20 grado, on a kenwood kd500 tt, it happened! awesome to see, wish id videotaped the occurrence. it oscillated in a circular path as viewed from the front of the cartridge.
im sure it has to do with the cantilever, tt, warp freq. i put a 1 gram blob of black modeling clay on the headshell, rebalanced the arm, and reset the vtf. all was fine from then on. all i did was to move the resonant freq out of the range. its worth a try, and you can just find another 1 gr weight to put there.
I had the same problem with a very light deck.  Balancing the table solved the problem all on it's own.  I did eventually buy a heavier deck but I'm hoping that the change of cartridge to the Grado won't bring back that horrible sound.