I have seen a few threads like this when I search the topic but the resolution is always that it is not available on the free version, but I am currently using the paid version. I have tried setting up the variable and passing it to the function or just calling it directly and it does not seem to work. I would assume there is some error in how I am calling it but am a bit out of ideas at the moment.
Hm I am currently using a recast graph. When I try to define the variable as IRaycastableGraph I get a different error. I have also tried AStarPath.Active.Data.recastGraph
Ah that was definitely it, forgot it just adjusted the previous points lists given in the function argument. Sorry for the confusion and appreciate the quick fix.