My concern is the issue that would have allowed you to visually notice a change in azimuth as well as the over damping. A few things that come to mind:
If the plane of the paddle was too far out of relationship with the cartridge mounting surface this might have created an azimuth issue. I've seen arm wands that have spun within the paddles T support which cause this. If the paddle had contacted any part of the cup during its arc across the LP it would have caused similar problems.
A difference in vinyl thickness and or a variability in how the record was clamped down to the platters concave could have been viewed as a misadjusted azimuth. This is one of my personal dissatisfactions with the early Well Tempered system.
Over time the viscosity of the tonearm damping fluid increases which is just as unnoticeable as the wear of a vacuum tube. The difference isn't noticed until its been replaced. Some have used the much more viscous platter cup fluid in the tonearm cup. Some have even admitted to using automotive additives for these fluids.
In any case there may have been an issue with the setup of your Well Tempered tonearm. All the best with your current collection of spinners, very nice.