We have similar case as mentioned in https://community.atlassian.com/t5/Portfolio-for-Jira-questions/How-to-sync-from-JIRA-to-Portfolio/qaq-p/595085 , but in server version.
Main question how to do sync from jira issue to portfolio ?
example: Members information is updated from portfolio to Jira assignee, but we did not manage to get update from assignee to Members field.