Sync Assignee of linked Jira Service Desk ticket to Jira Cloud Issue

[Julia Ysabel Yuzon]

hello! we had set up an automation months ago that when an end-user submits a ticket via our Jira Service Desk, it will auto-create an issue within Jira Cloud containing the necessary details. When we assign the ticket/change the assignee via Jira Desk, it will auto-reflect in the linked issue in Jira Cloud.

Recently, we had set up a Zapier flow to create a Jira Desk ticket when one of us (admins) would emoji react to a Slack message. Also, whoever reacts to the Slack message would be the Assignee in the Desk. I had set that up successfully. And since we had an automation before, as I mentioned above, that auto-creates an issue in the Cloud, the recent Zapier flow obeys that automation, hence creating a linked/cloned issue in Cloud. 

However, I noticed that some of the linked Cloud issues via the Emoji automation do not reflect the Assignee reflected from the Desk - it remains as Unassigned in the Cloud.

How do I go about this? any automation rules in the Cloud I could create?