This seems to have gone to -10 and then went up according to this, which matches what your comment had said that you were seeing -10 on your android.
Edit: (actually it had gone all the way to -15) and seems that this website has been still stuck at -8 upvotes at the moment of this comment and this link has also been the proof for me to finally see/confirm this as the submission now has positive upvotes.
It is hardly a satisfying answer, but I haven't the foggiest what caused it. I submitted it the same as I've submitted many other submissions in the past.
My comment on the other thread meanwhile wasn't nice at all, but it was also misdirected, and meant to refer to Hacker News rather than your own site.
(I like the style, too. It's good to see Helvetica get a deserved reevaluation, now that the millennial generation is aging out of even being able to imagine we are cool. Or ever were.)
My own profile on this website may help elucidate my perspective on the matter. I'm both shadowbanned and have applied a hundred-year "noprocrast" countdown, and it's frankly embarrassing how little that actually does to get the website not to accept those few contributions I still care to make.
It is as if the folks who run this place were getting a little desperate! - both for the "crowdsourced" unpaid work that goes into making this website worthy of interest, and for the last dwindling taste of what was once termed the "hacker spirit" by fringey weirdo ideologues like Stallman and Barlow.
(The idea that HTTP GET requests must be idempotent for safety, for example, has totally passed by this site's implementors and maintainers, or maybe never made a dent. Hence the subject of this very thread!)
In any case I regret the misplaced comment, and apologize for the dismay it likely caused. This website is embarrassing, and has just about run its course. Yours is not embarrassing at all, and I hope you're just getting started!
Maybe there is an API to downvote posts and some bots found it?
Edit: Actually I would wager that it’s some kind of automatic downvoting when the system detects bad votes or comments. Something like “friends shouldn’t vote”. Since we see voting on posts and not comments we could see it go negative.
I suspect there’s downweights the system can apply - and if five people voted it up, the -5 downweight was applied, and then four of the upvotes were removed, you’d end up at -4.
https://news.social-protocols.org/stats?id=48104663
This seems to have gone to -10 and then went up according to this, which matches what your comment had said that you were seeing -10 on your android.
Edit: (actually it had gone all the way to -15) and seems that this website has been still stuck at -8 upvotes at the moment of this comment and this link has also been the proof for me to finally see/confirm this as the submission now has positive upvotes.