Permalink to comments works incorrectly

We're using JIRA 6.2.7. When I click the icon that says "A permanent link to a comment" that's displayed to the upper right of every comment I see this behavior (FF, Chrome and IE 10):

1) My browser follows the link, showing the issue and highlighting the comment

2) The URL shows the full link, but 200 msec later, the URL shortens to just show the issue ID.

• For example, the URL shortens from
  • https://jira.atlassian.com/browse/JRA-34998?focusedCommentId=605922&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-605922
• To
  • https://jira.atlassian.com/browse/JRA-34998

I assume this is a kind of regression bug.

This issue is reproducible in this issue tracker https://jira.atlassian.com as well. See attachment. GIF demonstrates the appearing of permalink in the URL bar for short time. After finishing of loading page the link is replaced to issue ID link.