Hmm, not that I've taken a second look, I noticed that I added a hidden image hosted on their servers when I implemented the ads. It's used for counting the ad impressions, but it looks like it drops a 1-day valid cookie as well :/
It's a little funny to me you added a literal tracking pixel to your website from a VPN company and then came to HN to preach that you don't do any tracking
That said, due to third party cookie changes, tracking pixels have very limited usefulness these days and it's unlikely it actually tracks people over a full 1 day period