Here are my pre-2020 HN comments, with 3 double hyphens in 8 comments: https://hn.algolia.com/?dateEnd=1576108800&dateRange=custom&...
As I was in the process of typing the search term to get my comments (and had just typed 'author'), this happened to come up as the top search result for Comments by Date for Feb 1st 2000 > Dec 12th 2019: https://news.ycombinator.com/item?id=21768030
Note that I wasn't searching directly for the double hyphen, which doesn't seem to work -- the first result just happened to contain one. If I'm covering for the Anthropic guy, I could be lying about the process by which I found that comment, but I think you should at least see this as sufficient reason to question your assumptions and do some searches of your own.