Tom Tango explains new observations of pitch spin, based on a statement by Jared Hughes:

“There was absolutely no difference in how the ball was rotating,” Hughes said.

TheAthletic.com

The various radar tracking systems inferred the spin of the ball by calculating back from observations of the balls flight. Statcast now measures spin directly, and Hughes is correct. Baseball Savant how shows both interpretations of spin. I suspect the next step is to see if big gaps in observed and actual spin is good or bad for the pitcher.

Many years ago I attended a baseball research conference that discussed the physics of spin extensively. At the end, they showed a pitch in slow motion that moved very differently than what the spin access would predict. It was clear then that spin access is only one variable in controlling the flight of the ball. Maybe mastering the other variables is what separates the good from the great.