If this is truly a Universal Link, then this shouldn't have happened. I'll take a look at the external app launch code.

Issue 809975 has been merged into this issue.

809975, was added as RBS. Peter, did you have a chance to look at this bug? I know I'm a new Download owner, but I don't have time to look at this problem as I've been swamped with navigation bugs.

Given that lack of further comments, I assume that I haven't looked at this again after comment 1.

I would disagree with issue 809975 being set as RBS since it is not a crash and we know this has been happening for a long time. There's a easy remedy for the user (reload the page).

Then I will fix this by New Download Manager. M67 would be the earliest we can ship it.

 Issue 818339  has been merged into this issue.

We have the exact same issue with our App.

Steps to reproduce: 
1.) Install Authentiq App, open it and pass the welcome screens
    https://itunes.apple.com/us/app/authentiq-id/id964932341?mt=8
2.) Launch Chrome and visit https://oauth2.demos.authentiq.io/?display=page
3.) Click on "Sign in"
4.) Either go back from Authentiq app to Chrome or click the "Sign in" button in the App

Observed behaviour: 
Download manager UI is displayed.

If you test with v1.2 of Authentiq App, note that we force chrome to open a new tab after sign in from the App, so the problematic tab still exists in tab manager of Chrome. Version 1.2 of our App does this to mitigate the issue.

Notes:
In our server logs, we can see that Chrome does a HEAD request instead of a GET.

We plan to fix the bug in Chrome 67 with the New Download Manager UI.