Hello and super sorry for the late reply. I missed your post..
Right now subgraph variables mapping does not work with dynamic subgraphs (meaning subgraphs that change reference via blackboard variables). It is basically one or the other. Since int his case the subgraph is assigned dynamically, keeping a “map” for each potential subgraph automatically is not possible. I could implement something for this but it will require user input to “store” the mapping (as well as cleaning mappings that are not longer required). So is what you suggest the following workflow?
1) Assing a subgraph to the variable that the subgraph node is reading.
2) Go to SubGraph node. Make the variable mapping and store the mapping (manually via button).
3) Assing another subgraph to the variable and repeat the process.