Import Datafields from prior Export

Hey there,
I want to export my data fields from the Director config and reimport it on another instance. The configuration basket does not support data fields, so I tried to do it via cli. The export
icingacli director export datafields > /tmp/datafields.json

works fine and I get a very nice JSON. When I want to import the fields with
icingacli director import importsources < /root/datafields.json

ends with following error:
ERROR: ErrorException in /usr/share/icingaweb2/modules/director/library/Director/Objects/ImportSource.php:92 with message: Undefined index: source_name

Director Version: 1.7.2
icingaweb2 Version: 2.8.2
icinga2 Version: 2.12.1-1

Thank you for your tips

Stephan

Sorry, I missed that this is not longer the first choice help community. I will open the same on icinga discourse.