Using JIRA Server Core 6.3.12 and HipChat 2.0 build 1.4.3 (2016.07.11.082020).
We have configured integration between JIRA and Hipchat.
When JIRA issues are mentioned in Hipchat, it does pull in the summary information correctly. In JIRA, the issue does show the link that says "Issue mention in N rooms"
When a user clicks on that link, they are prompted to confirm/grant HipChat access. If the user clicks confirm/grant in all cases, ultimately a message is displayed over the JIRA window that says "failed to get issue mention details".
Admin users (JIRA full admins and HipChat full admins) don't necessarily see this error.
We did test this with the issue mentioned in a public HipChat room.
Any ideas?