I thought of that too when I saw it. But after a second I decided it's not a move. Oliver doesn't seem like the type to do moves.
Here's the reasoning: He must cut the ball enough to go into the pocket, but has to come very close to fouling to do so. He is definitely hitting the fat side of the pocket to make the shot. If he hits the middle of the pocket, he fouls... it's that close.
If the balls are dirty, there is collision induced throw. The three will undercut a tiny bit due to that extra cling between the balls. If the 3 is barely squeaking in and undercuts due to throw, it's gonna rattle out. So he's just taking extra care to cover all his bases.
Also, it looks like they used one of those professional markers. You can't really get the position wrong with one of those.