The page looks like this:
https://bitbucket.org/ If enabled, this will send notifications when issues are raised.
I am not sure what you are referring to, there is on attachment on this issue and I don't see an inline image.
I don't find the text https://bitbucket.org on the issue notifications admin screen.
This seems related to Issue 4897 as I can only reproduce it when I access the repo via its custom URL. When I access the page via bitbucket.org it looks just fine.
Since the site redesign, this error is now obsolete.