Product Hunt launch question: how are votes counted and filtered?

We recently launched on Product Hunt and noticed something I don’t fully understand.

We asked our users for support a bit late, and all of them had new Product Hunt accounts. From what I understand, some votes from newer accounts do not count and may be filtered.

But I also noticed notifications that someone upvoted the product, while the total number of votes didn’t change.

How does Product Hunt actually calculate the final vote count?

Would appreciate any insights from people who have launched recently.