This is pretty simple.
On S/X all non-P vehicles list 0-60 without rollout (ie the real life 0-60 time) and the P models list 0-60 WITH rollout (the sexy car magazine number with 1 foot rollout that isn't how 0-60 works in real life).
The Model 3, until this week, listed all versions with the real life 0-60... 5.1, 4.5, and 3.5 respectively (and now 5.6).
Starting this week they've switched the P3 to use rollout like the P models of the S/X, thus knocking 0.2 off the posted time without actually being any faster.
No cars got faster, or slower, they just switched to magazine numbers instead of real world ones on the P3, as they've always done for the S/X P models.
The only weirdness here is that every other car maker includes rollout for ALL their cars so it's easier to compare them fairly.
Tesla only does it on the P models to make the P look more "worth it" compared to the non-P