A sufficiently long comment without spaces can break the page's layout:
1 Answer
If you type way too many characters into the comment box, some of the text will overflow and thus being the example you linked above. The maximum amount of characters that can be typed until the text overflows is unknown to me...
But anyways, comments like that should be flagged as not constructive or too chatty as it is excessively long for no apparent reason. So either someone should fix the code to allow better formatting or just lower the limit of characters you are allowed to type in as a comment. 600 characters seem a little too much for a comment.
That's my answer from the question marked duplicate of yours...