Titles with less than 5 characters result in incorrectly aligned text on first subsequent line

[R. Tyler Croy]

Kind of a weird bug, but it does appear to be tied to the number of characters in the title:

Using the following slide:

# Title

* this
* is
* a list

With five characters in the # title, things look correct:

If I use a four character (or fewer) title, then the first subsequent line doesn't align properly:

[Michael Göhler]

Can't reproduce. Which OS?