It might be that your NLU model gets confused by input in that field (e.g. if it’s just a person name or something) and so it could classify it as a number of intents. So you could make your story something like:
* blabla_intent OR blabla2 OR blabla3
- custom_action_freetext
The submit() function can just return [] if you want. Or you might want to make an API call there or something that uses all the collected slots to get some information.