External data reference only returns list

Infos:

I have set up some custom ticket attributes that reference an external data source (a webservice I have setup). I am unable to get this to work unless the value/s that I look up are in a list. This means that when I am creating a ticket I need to manually select the value from a drop down list even if list only has a length of 1. Is this expected behaviour or is there a way for the attribute to be automatically populated if the list length is only 1?

  • Used Zammad version: 6
  • Used Zammad installation type: (source, package, docker-compose, …)
  • Operating system:
  • Browser + version: chrome

Expected behavior:

External data reference attribute is populated with value if value list length is 1.

Actual behavior:

I need to manually select the value from a drop down list of length 1 during ticket creation.

Steps to reproduce the behavior: