Problem with date extraction

[danielhomsa]

I am using duckling to extract time entities in RASA, but I am having a problem when using a sentence like "before 1800" or "between 1700 and 1800" where I am getting as value the current year.

Here is an extraction:

{
   'start':26,
   'end':47,
   'text':'between 1700 and 1800',
   'value':{
      'to':'2019-05-14T18:01:00.000+02:00',
      'from':'2019-05-14T17:00:00.000+02:00'
   },
   'confidence':1.0,
   'additional_info':{
      'values':[
         {
            'to':{
               'value':'2019-05-14T18:01:00.000+02:00',
               'grain':'minute'
            },
            'from':{
               'value':'2019-05-14T17:00:00.000+02:00',
               'grain':'minute'
            },
            'type':'interval'
         },
         {
            'to':{
               'value':'2019-05-15T18:01:00.000+02:00',
               'grain':'minute'
            },
            'from':{
               'value':'2019-05-15T17:00:00.000+02:00',
               'grain':'minute'
            },
            'type':'interval'
         },
         {
            'to':{
               'value':'2019-05-16T18:01:00.000+02:00',
               'grain':'minute'
            },
            'from':{
               'value':'2019-05-16T17:00:00.000+02:00',
               'grain':'minute'
            },
            'type':'interval'
         }
      ],
      'to':{
         'value':'2019-05-14T18:01:00.000+02:00',
         'grain':'minute'
      },
      'from':{
         'value':'2019-05-14T17:00:00.000+02:00',
         'grain':'minute'
      },
      'type':'interval'
   },
   'entity':'time',
   'extractor':'ner_duckling_http'
}

Does someone knows why this is happening or how to fix it? When I use a phrase as "in 1700" duckling gets the value correctly, but when using any other sentence I get this.

I also did the test directly to the duckling container and I get the same issue.