This example is using: Mercurial Fails to Update to A Revision Due to a File Name
The normal view shows the code lines all broken up, extra lines, etc. But in edit mode it basically looks like what I would expect.
I'm not sure if this is new, normally I thought both views looked the same all the time. At least I've never noticed this before.
Update - I did edit that question to fix the readability. All that was needed was to remove the triple backtick style of formatting and use the spaced indentation for the code blocks. So I guess it was the triple backticks that are not rendering consistently.