Thanks for confirming this. There was some speculation last year about partial shadow bans for voting,* and it's good to hear an authoritative answer.
* https://news.ycombinator.com/item?id=30317059
When this happens to an HN account, is it permanent or can it be reversed if the account stops upvoting "bad" comments? If it's permanent, affected users would like to know. Evaluating comments and determining whether they should be voted on can take a long time, and the affected users could save a lot of time if they knew that their votes would never count again.
I know that's problematic because it depends on us seeing things and manually doing them. I'd love to automate it—not just because it would be fairer but because it would be less work for us! But I don't know how to write code to do that.