Our team page (https://bitbucket.org/<team>/) keeps showing the call-to-action block ("Teams connect with HipChat!") in the right sidebar. After closing it (right upper corner) it dissapears.. only to be shown again on the next refresh.
Are you still seeing this? I'm unable to reproduce (closing that HipChat box is permanent for me on several attempts with different teams), and the 404 you note is actually unrelated. If you're still seeing it I can do some additional investigation.