Generally speaking, domains that declare compliance with EFF's Do Not Track policy (https://www.eff.org/dnt-policy) are not supposed to engage in tracking. It's possible the cookies you noticed are compliant but it's also possible that you noticed somebody breaking their promise.
We could look into what's going on here if you email us at extension-devs@eff.org with information about what these domains are and where you noticed them.
