Interesting! I get all Reddit results on my laptop (Safari), but on my Android (Edge and Chrome) I get Good Housekeeping and NYTimes before Reddit. Some kind of ad? Though when I click on the three dots next to the result, it says it's not an ad. Odd.
Yes, there's a particular bug that sometimes happens on mobile with some queries. It's relatively recent; we're aware and working to resolve it, because site: really should only show content from the indicated site.
Any Googlers want to chime in?