The value in that variable is an uid map. The val() func doesn’t support convert the uid map to string. As far as I know.
What is the expected result?
It seemed simple and straightforward to me. You want to define that some projects are “new” and the “projects” edge just points to all projects (new or old). And “new_projects” for projects that you consider new. You need to define how to identify what’s new from what’s not. Maybe using Facets.
If you want to use edges to define what is new or not. Just remove it on one and add it on the other edge.
Cheers.