Yes, the reference wll be lost in playmode, even if it allows you to assign a reference. The only reasons it allows you to assign a reference is only in the case you actually assign a prefab for example (which IS an asset and not a scene reference).
Regarding the bug, thanks. I will take a look at it, although normaly an asset graph not attached to a controller shouldn’t show the variables panel at all.
Yes you can have multiple flowscripts, but not multiple blackboards. All FlowScriptControllers will use the same blackboard. This is done by design, so that they share the same variables 🙂