It's not necessarily blatant. I know there are exceptions where the three second count is "temporarily suspended." Not stopped or reset, but held in place. So if a player who has been in the lane less than three seconds receives the ball and goes into his gather/shot attempt, the count is suspended until that attempt ends. If he shoots it, no call is made. If he doesn't end up shooting and instead dribbles/passes the ball, then a three second call is made.

Technically, Embiid was in the lane less than three total seconds when he received the ball. He then immediately went into his "moves" that, while briefly still at points, were a part of him gathering to shoot. So, a ref could argue that he started gathering at < 3 seconds and he allowed him to shoot.

I don't think it's a great interpretation, because he was making post moves as opposed to starting a running dunk motion, but it's not as superbly blatant as people are saying it is.