In answering a question earlier today, I used some funky formatting. While this formatting might not be the best way of doing things, there is still a bug where the preview question doesn't look the same as the published question. This is what I used:
In the preview, it looks like this:
But in the published question, well, it looks like what is above. On my screen, it looks like this:
Feel free to edit the question and see the code for yourself. The bug here is that the preview (while typing the question) doesn't look the same as the submitted question (or answer, both have the same issue). In the preview, there are no extra lines, but once submitted there are 3 extra lines in each "segment".