Comments on prior versions broken

When there are commends on a pull request for a prior version of the file that are now hidden it displays an icon that looks like a word balloon with an elipsis in it and a badge/label with the number of hidden comments.

Usually when I click this they load in an overlay via ajax. Now the spinner never goes away. I see a couple requests go out to google analytics, and then a second or two later a request aimed at
https://bitbucket.org/api/1.0/repositories/

{account}

/

{project}

/pullrequests/

{pr number}

/updates?since=2013-12-10T18%3A23%3A43.275542

The ajax response that comes back over the wire is something like:

{"destRevMoved": false, "rebased": false, "approvalsAdded": [], "lastModified": "2013-12-10T18:24:03.369364", "commentsReplied": [], "approvalsRemoved": [], "updates": [], "commentsDeleted": [], "prDetailsModified": false, "commentsEdited": [], "commentsAdded": [], "viewers": [], "anchorMoved": false}

Not sure if that helps, as it seems like it's an occasional ping for general updates rather than something related to the UI action I took.