I was "homebrewing" TNBehavior, before I learned that TNBehavior existed and ran into it not finding RFC calls, even though it previously had (order issue I presume).
If you expect or recommend users to use TNBehavior, when a RFC not found error occurs, I'd suggest doing a quick iteration down the inheritance chain to see if it contains a TNBehavior. If not found, throw a warning or error, stating that you force/recommend the user to use TNBehavior. If you want to leave it as a choice, mention in the warning to flip the TNObject.rebuildMethodList bool to true.
It should alleviate some of the questions before they come to the forums begging for help, like me :-).