This past week one of my trainees had a triple pop: training 1v1 forwards, a guy popped in driving, handling and inside shot.
THough it's nice and all, the total increase in his skills isn't likely to be any different than my other trainees who didn't show a pop. It's just that this guy's sublevels were close to rolling over to the next whole number. And the increment in his play isn't going to be different just because he crossed some special threshold (now, crossing that threshold to get the visible pop would likely increase his resale value, given that a prospective buyer has no indication of the sublevels).
Still, it's nice to see that little up arrow next to three skills.