When I look at my answer here, the link and the diagram link are "messed up". But if I click on "edit", the preview looks perfectly fine. It is just me, or do others also see this anomaly?
This actually had nothing to do with the periods in the LaTeX. This was pure coincidence, based on timing and this bug I introduced on Friday.
At the time you started writing your answer, this bug wasn't introduced yet. That's why everything looked correct for you in the preview. By the time you submitted your answer, the bug was in the system, causing the broken rendering. By the time robjohn made the edit, the bug had been fixed again, so the rendering was correct again. It would have looked correctly with the periods as well.
Apologies about the confusion (and thanks robjohn for jumping in to help).