Unable to get Mesh Offsetting to work in 4.25

So I followed along with this lecture all the way to the end, and I’m getting an interesting error. Here’s the error code output.

The Result of this is that the whole car just jumps from position to position on server updates, and all that interpolation work isn’t seen at all on the mesh. Any help sorting this out would be appreciated. As I say in the topic title, I’ve been working through this course in 4.25.