UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.170 Safari/537.36

Steps to reproduce the problem:
Likely required pre-conditions: some browser extension that requires you to be logged into Chrome that somehow initiates a "Sign in to Chrome" dialog window. 

Actions I took to encounter the problem:

1. Changed Google password
2. Attempted to load a page requiring Google authentication which redirected to Google login page as appropriate.
3. "Sign in to Chrome" Pop-up dialog opened asking for my username (which was pre-populated).  
4. Hit "next" and started typing my new password

What is the expected behavior?
I should have been able to complete the authentication process in the window that opened.  That is, whatever triggered the "Sign in to Chrome" window to open should not have been able to auto close it so soon, particularly while I was actively interacting with it.

What went wrong?
Approximately four seconds after the "Sign in to Chrome" dialog window opened, while I was typing my password in the dialog, it closed and re-opened, asking for my username again.  Even without hitting "Next", the dialog would close and re-open after approximately four seconds.  Even if I closed the window, it would re-open approximately four seconds after it had previously appeared.

Did this work before? N/A 

Chrome version: 66.0.3359.170  Channel: stable
OS Version: Debian rodete - 4.9.0-6-amd64
Flash Version: 

I could not hit "next" and type my new password fast enough to properly authenticate to chrome with the dialog reloading ~every four seconds.

Killing and re-launching Chrome resulted in the same thing. 

Killing and re-launching Chrome using "--disable-extensions" resulted in the dialog *not* opening, and I was able to authenticate to the browser inside a browser window (not a pop-up dialog), though I'm not sure exactly what triggered that login window to appear in a normal tab.

Note: I recognize this is likely triggered by a misbehaving extension of some kind, but I also feel a "Login to Chrome" dialog window should get some sort of special treatment even if an extension somehow triggered it.