UPD: The problem is fixed now.
Today I tried to write a comment with formulas, something like this:
What I got in the comment preview (and if I actually post this in the comment or a blog):
The same happens if I copy my old comments with a couple of mid-length formulas in the same sentence: they don't look the same, line splitting occurs. In fact, here is the code that is generated:
If $$$a$$$ and $$$a + x$$$, then. If you remove spaces in "a + x", line breaks disappear. Also, for example, abcd generates line breaks, and abc does not etc.
Does anyone have this problem or did I accidentaly change some setting for my account and broke everything?