Deleted JIRA mentions are not updated in the JIRA Issue

1. create a JIRA issue
2. create a page in Confluence
3. mention the JIRA issue in the Confluence page
4. refresh & check the JIRA issue is updated in the mentioned in section
5. copy the Confluence page
6. create a fresh page adn add the JIRA issue mention to it
7. refresh & check the new copy page appears in the mentioned in section on the JIRA issue
8. edit the copy new page to remove the JIRA issue mention, replace it with the word "deleted"
9. refresh & check the JIRA issue is updated

Edit: the copy page step is not necessary to reproduce.

Expected Behaviour
The JIRA issue updates to match the confluence page

Actual Behaviour
The issue no longer mentioned in Confluence still appears on the JIRA issue. It appears the deletion of the JIRA issue is not communicated back to JIRA.