Question Copied .vfx graphs missing all subgraphs, replaced by "empty subgraph operators"

Hi,

If I copy my .vfx files and .vfxoperator subgraph files into a new project, all of the subgraphs are disconnected and missing from the graphs, and replaced by Empty Subgraph Operators.

I've tried importing the subgraphs in to the project first, so that they are present in the project before importing the full graphs but this doesn't make any difference.

Any ideas how I can import my graphs to another project, and keep the subgraph connections intact? It's a lot of work to rebuild each graph, replacing all the subgraphs and setting their original values.

Thanks