I couldn't reproduce this on 63.0.3239.132 stable on 10.13. I'm presuming from the video that you didn't have any other incognito windows open in the background or hidden in some way as that would keep the incognito session open.

I noticed that the non-incognito window is authenticated to the same account you're logging into incognito with, but that shouldn't affect this.

+privacy team to investigate.

This should only happen if there is a second incognito window somewhere because incognito state is deleted when all incognito windows are closed. Please check if that is the case. 

https://chromium.googlesource.com/chromium/src/+/master/docs/security/faq.md#What-are-the-security-and-privacy-guarantees-of-Incognito-mode

FWIW, the explanation in #2 is not well-understood and has been the source of all of the reports of this behavior I've seen. After confirmation, please dupe to  Issue 722122 .

Thank you for the quick response on this. I hope this isn't a bug.

After completely closing Chrome - then trying to reproduce the issue, I was unable to do so. There is a possibility the explanation in #2 happened last night.

If this is the case, then the explanation in #3 is also important here. To a typical user, why would one assume that if I had multiple Incognito tabs/windows open that they would all share the same cache until I closed all of the windows/tabs? The description of Incognito when one opens a new tab is:

Chrome won’t save the following information:
Your browsing history
Cookies and site data
Information entered in forms

This is not true. Data is being saved in some form of Cache. I also understand this is somewhat of a feature so people can persistently use Incognito like a normal web browser. If that is the case, then I think the team should consider a feature in addition to the current Incognito called "isolated incognito". This feature could be buried in the UI (similar to how viewing website certificates was moved) as most users would not need to use this on the regular basis. Just some thoughts. Thank you again for quickly looking into this. 

Multiple Incognito windows share the same Incognito profile, same way as multiple regular windows share the same underlying persistent profile. From that perspective, it's consistent.

Nevertheless, I agree that this is a common complaint, and that partitioning Incognito per browser window would be a more understandable user experience. Unfortunately, this is a significant architectural change to Chrome.

In shorter term, we should probably think about a UI solution to remind users of this fact.

+cc maxwalker@ FYI

And yes, I think the Incognito tab peeking from behind the regular tab in your video confirms that this is inded  issue 722122 . Let's move the discussion there then.

Actually, there's an even older one: issue 464985.