Posts starts with a directive are not correctly generated.

[Determinant]

To reproduce the issue is simple: just create a new post with merely a code directive or line blocks. The generated result doesn't have corresponding <pre> or <div>. However, if we append some characters before the directive, the result will be correct.

[Kwpolska]

Reproduced. Happens somewhere in the post-processing bit, as the cache/ files are correct.