I ran into a lot of bugs trying to pass variables between graphs (can we have subgraph support?) So I’ve resorted to using the Send/On Custom Event and Bundles to send data between them. Unfortunately, the bundle attribute set gets baked in the first time the node loads and doesn’t update when the bundle contents change until a stage reload (requiring a save!)
This causes problems for downstream listeners to that event that are using dynamic queries (Has Attribute) and generally makes working with custom events a pain.
Worse still, because Extract Bundle won’t update its outputs until it has been executed in an Action Graph I have to build a dummy pull with a Bundle Inspector > To String > Print Text so the outputs will update.
This makes working with dynamic data a frustrating and time consuming experience. See also: Bundle Constructor not copying values, etc.