Help required with tracking problem

Front end: Ariston RD11s with SME3. Selection of arm wands including Integrated SME/Ortofon 30H, Sure V15 IV, Ortofon MC1, Goldring 1012x and the Stanton 681 EEE latest version.
The problem is with the Stanton, there is one particular record CBS 32509, "Fame and Price Together" track 1 "Rosetta" where Georgie Fame sings from the left channel and Alan Price sings from the right channel (very 70s left and right stereo). Georgie Fame's voice is distorted (mis tracking) with very pronounced sillibance. I have tried everything from using with and without brush (slight improvement without brush)increased tracking weight to rediculous level all to no avail. I could understand it if the distortion occured with all the cartridges but it only happens with the Stanton. All other tracks and all other records are fine (maybe just a slight hint of sillibance with the Stanton but nothing too extreme). The cartridge is set up correctly using an electronic balence scale and a Mayware cartridge alignment protractor. Lateral balence is even and the anti skate is correctly set for tracking weight.
Any suggestions please?
It could be I have a "slightly duff" Stanton but that would surprise me as Stantons are meant to be second only to the Sure V15 series in trackability.
I think it's a tracking problem with your 681EEE. The Stantons which tracked really well (they are discontinued now) were the 881S and its descendants, such as the 981 series and the 880 series (actually the same as the 881 but not calibrated). The 681 is a completely different cartridge...for one thing, it's a moving iron, whereas the 881s are moving magnet, and a very tiny magnet at that, made of samarium cobalt. The 881 magnet is smaller and lighter than the iron armature in the 681, and the cantilever is much smaller.
Something I forgot to mention:

You may be using an electronic stylus pressure gauge, but with BOTH the Shure V15 IV and the Stanton 681EEE you can't just measure it and leave it at that. The reading for the Shure must be increased by 0.5 gram over your desired tracking weight, and that for the Stanton must be increased by one gram over your desired tracking weight. This is because both have that pivoted brush. The first 0.5 gram of force on the Shure, and the first one gram of force on the Stanton, will only serve to raise the brush. After that, force begins to be applied to the stylus.

I like to track the 681EEE at 1.5 grams. This will result in a measurement of 2.5 grams. My Shure V15 IV seems to work best at 1.25 grams. You would need to measure 1.75 grams to do that.

If you don't want to use the brushes, you can lock the one on the Shure out of the way. On the Stanton, you must remove the brush by snapping it out to the rear of the stylus assembly, and then (IMPORTANT) rebalance the arm at the counterweight before resetting tracking weight, since you are removing about a gram from the arm/cartridge (the weight of the brush).