Pull-Request : can't add a comment (BB-5156)

Hello,

Since yesterday, we're unable to post comments on a pull request (number 48) made by one of our developer on the "tfbr" repository of our team account @telemetris. This seem to be exclusive to that particular pull request, as we were able to post comments on pull requests on other repositories, as well as on other pull request in the same repository.

When pressing the submit button, the button goes disabled and nothing happens. If we keep Firebug open during the attempt to add the comment, it shows that the ajax request fail with an HTTP 500 error (in the UI there's no feedback regarding that error, and the "Submit Comment" just stay disabled).

Looking at other recent issues, I'd guess this is somewhat related to issues BCLOUD-3608 and BCLOUD-4519