This is legal because it meets the definition of a switch up, which is a legal skill.
Loading Position/Load – Bases support a non-extended top person under the
foot/feet in preparation for a stunt or toss.
Switch Up – A top person starts with one foot in a load, is released and lands in
a vertical stunt on one foot or both feet.
3.5 ART. 4 . . . A switch up caught by the original bases is permitted as an exception
to Rules 3-5-2 and 3-5-3.