I think it mostly happened when HN became flooded by Reddit users. One of the reason I think this is because of how HN and Reddits way of dealing with new lines is different. In a lot of the comments on HN that I would consider to be fitting on GPs point you’ll see a format a long the lines of this:
This is the first line of my paragraph.
This is the second line of my paragraph.
They are separated because HN and Reddit formatting is different.