Dev Close Browser Delay

HotCakeX "Does it happen when you are on a specific website or happens even when there is only NTP open?"

It doesn't seem to make any difference what tabs are open or closed. 

I have replicated the difference in response between Stable and Dev with the two browsers operating the same computer, with identical tabs opened.   

Because I sync startup on all instances of Edge Chromium tied to my MSA, both Stable and Dev on all my computers start with two Bing tabs opened; the anomaly occurs even when only those two tabs are open and nothing else is open or has been opened. 

That did spur a thought, though.  I almost always have a Bing tab or two open when I close the browser, and it occurred to me that Bing could be interacting with Dev to create the problem.  I tested this by opening an instance of Dev and an instance of Stable on a computer, replacing both Bing instances in each case with other websites.  I repeated the test 10 times using a variety of websites as substitutes for Bing, the opened tabs always identical between Stable and Dev on close.  I saw no change in behavior no matter what I did.  So I don't think that Bing is the culprit.

I've also tested with a single tab (the NTP tab) open on Stable and Dev.   That does not seem to make a difference.

The only constant seems to be that Stable (as does Firefox) closes instantly when I click the "X", and Dev lags 2-3 seconds in most cases, sometimes several seconds longer.  It is very odd, and I can't account for it.