The line spacing on Q&A text has opened up making each line look like a separate paragraph. This is the same on Chrome / IE and on Android Chrome.
Are some of the guys in the basement twiddling with the knobs?
You're right, line spacing has been increased as mentioned here on Meta Stack Exchange: New post formatting
Many people don't like the change, and posts like Please revert the line-height change! and this answer are very popular right now.