Issue Summary

Jira does not clear Custom Field values when the Field goes out of scope/context by editing an issue to change its issue type.
For example, if the both the issue types doesn’t share any of the following criteria, the custom field will go out of scope/context and hence any past value in those out of context field(s) should be removed:

• Project or issue type scope
• Field Config
• Field Screen

Steps to Reproduce

1. Make two custom fields restricted to only one issue type/project, having different Field Configuration and Screens
2. The two issue types should have the same workflow
3. Create an Issue of the first issue type and populate the custom field with a value
4. Edit the created issue to to change the issue type

Expected Results

The Custom field that just went out of scope/context loses its value on the edited issue with the new issue type

Actual Results

• The custom field value remains "attached" to the ticket even though the field is no longer in scope
• If you move the same ticket back to its old issue type you would be finding the field still retained the value

This can impact a number of “dependent” operations viz., automation, cascading custom fields, groovy script conditions etc. AND it makes it tremendously difficult to troubleshoot any of the above impacts since there's nothing in the issue data (viz., REST API) which shows the old field or its value

Workaround

Using the issue Move action instead to change the issue type, clears the out of scope/context field(s) values correctly.