I just did a search in this forum for "single sign on" and some of the results show a bit of an issue with the highlight coding:
General Help & Support / Forum ong class="highlight">Singleong> ong class="highlight">Signong> On WB integration
I then did a search for "Sign On" and you get a lot of evidence. It seems these terms cause the problem.
I notice that this is only happening in post titles. Just thought I would point this out.