Thread url encodes + wrongly which results in "That message could not be found."

From my debug.log:

2011-10-26 19:48:22 unifiedInboxChecker.py:67 DEBUG: [{u'snippet': u'Good. got that all confirmed then :D', u'timestamp': u'1319654895712', u'thread_id': u't_4q52qKQYFZr+e/wAtR1O5w', u'single_recipient': u'1254765266', u'subject': u''}]

FBuntu opens the following URL: https://www.facebook.com/messages/?action=read&tid=4q52qKQYFZr+e%2FwAtR1O5w and results in Facebook saying ""That message could not be found."

Facebook itself prefers the following URL: https://www.facebook.com/messages/?action=read&tid=4q52qKQYFZr%2Be%2FwAtR1O5w