Adding a files field to a plugin page

I am trying to add a panel route for a plugin. On this page i want to create a form with a files element. Works great but the files element breaks. If i try to select an image i get this message in my console:

TypeError: Cannot read property 'field' of undefined

This is my form, when i exclude the files it works great.

<k-form v-model="subject" @input="input" @submit="save" :fields="{
  name: {
  label: 'Name',
  type: 'text',
       required: true
     },
     text: {
       label: 'Text',
       type: 'textarea',
     },
     image: {
       label: 'Your Message',
       type: 'files'
    }
  }">
</k-form>

Any tips and tricks?