Guys relax if the topspin is really heavy there is no way that it can bounce twice on the table. Actually, the topspin here is not heavy but light.
Try to make your heaviest topspin to land close to the net, the ball will go forward and out of the table because of the forward rotation.
Gatien didnt fully contact the ball on purpose (the contact is made at the end of his stroke and at the edge of his paddle) , he wanted to land close to the net so that he can take CCY out of position, notice that although is motion is a forward motion, the ball doesnt have a full forward trajectory but it goes more up and less forward
Another factor is that the shot is made after a backspin shot of CCY, which makes it easier for a loop like that (the loop must first neutralize/lift the backspin and add topspin, which is the same rotation around the X axis) . I
If the ball was no spin and gatien executed the same motion, 99.99999 % of times the ball would hit only once at CCY's side of the table because you need to execute 100% perfect topspin.
Which is impossible to do on purpose, unless you have a godlike talent and know by nature exactly how fast and when u need to contact the ball to make a loop like that vs a no spin ball