I have the opinion that undeserved initial downvotes usually end up with more upvotes than the post would originally get. If I see a grey comment that I think shouldn't be grey, I'll upvote. But HN isn't fully dynamic, so that upvote won't be visible to people who already have the page open, so they'll see it as grey too and may also be likely to upvote.

So maybe undeserved early downvotes act like a trampoline. Nice insight.

I've noticed this very consistently. It seems the users who jump on posts early are an entirely different sort from the users who wait for posts to gain some popularity. I could imagine various reasons why that may be the case, but they are just speculation.

This indeed seems to happen a lot in my experience. I mean I see it in almost all my posts, and then they usually go up (or not :))