It's something that you see occasionally. From time to time Google uses tracking urls like this for a small subset of users. They're collecting data about something they need to know about the SERPs.
Google cotinually tweaks the SERPs in many ways. Some changes are small and hard to notice, and others are very dramatic. But unless the statistics they collect say that users prefer the new one over the old, it doesn't get rolled out into wide use.
Yes, most of the time it is a direct link to your url.
But this thread is about something that many other people have noticed, not just me. Sometimes the Google SERP does not offer a direct link to your page but instead it first goes through a redirect script on Google.
You see this regularly on sitelinks, but sometimes it is even on the regular results link.