and the right wing is experiencing it.

When you pull hard and fast on the elevator, the angle of attack reaches the stall angle, and for whatever reason, the right wing is stalling before the left wing. Since the Left wing is still flying but the right is not, the airplane rolls to the right. Essentially a snap roll.

It could be caused by any number of things:

Angle of incidence may be a fraction of a degree higher on the right wing than the left

Subtle difference of the shape of the Leading Edge of the wing between the Left and Right sides induces the stall on the right wing before the Left side stalls

Rudder may be out of trim.

There's probably a few more possibillities, but these are the first three that came to mind.

My Super Sportster 20 and 40 both exhibited the same behavior, especially the SS20. I just learned not to pull hard and fast unless I wanted to snap roll. A smooth but hard pull would keep the airplane flying on both sides, but a quick, hard pull would get the accelerated stall every time.