JIRA integration broken in 8.15.3

We’ve been running successfully with the JIRA integration in GitLab for several months. However at some point in the last few weeks since upgrading to the latest version of GItLab links to issues no longer work. I upgraded to the most recent version (8.15.3) this morning to see if this was fixed and it still isn’t working.

The problem we have noticed is that clicking a JIRA issue hyperlink in either the title or body text of a merge request just takes us to the project issue browser and not the actual issue. See the screenshot below where the target of the hyperlink (in the bottom left hand corner) is the JIRA issue browser.

I am in the beginning stage. I mean currently, I am trying to integrate JIRA and Gitlab. But still, I didn`t get the solution. Can you please let me know how you use the triggering words with an example?