In order to streamline any process that involves modifications of UDT instances in an external tool (Export --> External Tool --> Import) it is necessary to export all parameters.
We have noticed the same behaviour that michael2 describes, in our project. We use an external tool to generate and ideally modify tags in a JSON format. The behaviour is noticeable when the tag is originally created in Ignition Designer. The behaviour does not occur if the tag is created externally as a Ignition-compliant JSON structure and imported into the tag database and exported again.
A similar behaviour can be seen affecting the “Raw Edit” option for a tag, where only parameters previously modified in Ignition are displayed.
Is there any chance this may be looked into by the development team?