This is illegal as performed.
The rule that applies here is 3.3.6.c.1, which states that inversions at prep level, which this is, “Require at least two people on the performing surface to be in a position to protect the head/neck of the top person.”
This very clearly doesn’t have two, and I would argue possibly has none. One person is on the top’s foot/leg, so not in a position to protect the head/neck. Once the top person goes over and behind the base, the base is no longer in a position to protect the top person’s head/neck. What we look at is “What if she kept going backward? What would that base be able to do?” He is not in a position that would have leverage to do anything helpful, and would likely end up landing on top of her.
The way to fix this using this personnel is to have the top just go to a ball position or flat body position on the base and not invert at all. It’s not that far from what they are doing now visually.