Spacing broken in included files

I created this issue previously under a wrong assumption. Turns out the problem is something else. Headings and other elements have nice spacing, UNLESS they come in through included files.

To reproduce:

test.md

Hello
===

foo

# Heading 

bar 

## Heading

<!-- include: test2.md -->

test2.md

# Hello 

## World

The result:

You can see that the spacing is gone between any element in the included file.