OnBeforeHover returns just an event rather than datapoints and an event

The title really says it all. I've attempted to set up an example in codePen (taking my code and boiling it down), however, the older versions didn't even call OnBeforeHover so I tried updating the versions, but I'm not at all familiar with the way in which scripts are loaded in via HTML tags, I think I've done it correctly, however, I have access to neither createPlotlyComponent nor plotComponentFactory in my code.

https://codepen.io/tim-logan/pen/NWgbBvr?editors=1010

I'm attempting to get enough data to make the hover only be active near the line rather than the entire fill, but it's a lot harder if I only have the mouse event.

Oh, and just for clarity, what I get out is NOT

{
  event: mouseEvent,
  points: [] /undefined etc
  ...
}

What I get out is just

event: mouseEvent

(The type definitions claims I should get the first out though)

Reproduce the OnBeforeHover behavior using the linked CodePen and inspect the component's type definitions, which claim the callback includes both an event and datapoints. Trace how the callback is exposed and confirm that the returned value includes the datapoints as well as the mouse event.