Markup at the beginning of a passage doesn't work because of header passage

I've noticed some weird behavior in Twine 2.0.11 using the Harlowe format. If I begin a passage with any kind of markup, such as a first-level heading:

#This is the passage title

and if I create a header passage, even a very basic one that simply sets a variable:

(set: $test to true)

then the first passage doesn't display properly. Instead of the first line showing up in a larger font (as a heading should), it displays like any other line of text and the hash mark appears at the beginning instead of being interpreted as markup.

Has anyone else noticed this? Is there a way to avoid it? Is it a bug, plain and simple?