I have Firefox set to "Delete cookies and site data when Firefox is closed" and also "Clear history when Firefox closes" (with everything set to clear except site data). Then I have an exception list of sites to save cookies and site data for (for example, youtube.com). The problem I have is that not all of the cookies are deleted when I exit. In addition to the sites on the exception list, there are others not on the list that remain. For example, in the screenshot, this is a cookie from gleam.io. It's setting it for domain .youtube.com, and this is one of the cookies that remains. I believe it's remaining because youtube.com is on the exception list. However, it should be deleted because it's for the gleam.io site. If I check the browsing data in Firefox after restarting, it shows up as site=gleam.io. Furthermore, I question whether the cookie should be allowed in the first place, since I have Strict Tracking Protection enabled, which should disable all cross-site cookies.