Rasa Slot Mapping multiple dates

I have a form that extracts two dates with duckling. But the slot_mapping doesn’t work if one of the dates is supplied in the message.

Working example

(Me)  - I want a vacation
(Bot) - When will you leave?
(Me)  - the 5th
(Bot) - When will you get back?
(Me)  - the 7th

this gives me the expected result:

The form parameters are:
 - minDate: 2020-03-05T00:00:00.000+01:00
 - maxDate: 2020-03-07T00:00:00.000+01:00

Not working example

(Me)  - I want a vacation the 5th
(Bot) - When will you get back?
(Me)  - the 7th

Gives me the result:

The form parameters are:
 - minDate: 5th
 - maxDate: 2020-03-07T00:00:00.000+01:00

As you can see in the latest example the slot mapping doesn’t work correctly when a date is provided when starting the form, how can i solve this?

ActionForm

class ActionRequestVacation(FormAction):

    def name(self) -> Text:
        return "vacation_form"

    def slot_mappings(self) -> Dict[Text, Union[Dict, List[Dict]]]:
        return {
            "minDate": self.from_entity(entity="time"),
            "maxDate": self.from_entity(entity="time")
        }

    @staticmethod
    def required_slots(tracker: Tracker) -> List[Text]:
        return ["minDate", "maxDate"]


    def submit(self,dispatcher: CollectingDispatcher,tracker: Tracker,domain: Dict[Text, Any],) -> List[Dict]:

        print(tracker.get_slot("time"))
        dispatcher.utter_message()
        return []


hi @Marc - welcome to the forum! Does it look like the NLU output is correct for I want a vacation the 5th ? A good way to test is to run with rasa shell --debug