Kia Ora,
Working on setting up Automation rule between two projects (one is JDP and the other is JSP).
I have successfully setup a automation rule from a value change in JDP to then edit linked issues (e.g., relates to) corresponding field.
However, when I try to setup a automation rule going the other way (value change in JSP to then edit linked issues (e.g., relate to) in JDP the rule fails,
I have create the automation rule as follows (from value change in JSP to edit related field in it's linked issues (e.g., in JDP):

I have also typed in the box below Business Value Outcome: {{triggerIssue.customfield_10504}}
I have research round and round but can't get the field working... my audit lot is:

When I go to Jira Setting -> Custom Fields... I'm unable to see "any of the JDP" fields in this view.
TIA for any support.