You are correct. It seems in the number of different permutations I tried to make this work, the correct markup broke because of my use of an ! in the heading. By the time I determined that symbols were broken, I had mangled my markup to eliminate the closing ==.
Which just makes the symbol problem even more of a problem…
So, it seems that handling of a line that begins with " ==" but does not end with "==" is not great. I guess it could be considered broken markup and the bad output considered acceptable, but even then it seems like it could be handled a little better…
Thank you for the followup.