UserAgent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3472.3 Safari/537.36

Example URL:
http://sinst.html.xdomain.jp/zengaku/jkkn/chrome_bug6.html

Steps to reproduce the problem:
1. Type a Javascript below:

window.onkeyup=function(){
	console.log("up");
}
window.onkeydown=function(e){
	if(e.altKey){
		if(e.keyCode===65){
			console.log("Alt+A down");
		}else if(e.keyCode===81){
			console.log("Alt+Q down");
		}
	}
}

2. Open a Javascript conosole of Devtools in Chrome Canary 69.0.3472.3

3. Press "Alt+A", or "Alt+Q"

4. Check the output of the console

What is the expected behavior?
Keyup event always fires on any keys.

keys:                  console says:

Alt+A           ->   "Alt+A down"
keyup of A    ->   "up"
keyup of Alt  ->   "up"

Alt+Q           ->   "Alt+Q down"
keyup of Q    ->   "up"
keyup of Alt  ->   "up"

What went wrong?
Only after "Q" key, the keyup event doesn't fire.
Console doesn't display "up".

keys:                  console says:

Alt+A           ->   "Alt+A down"
keyup of A    ->   "up"
keyup of Alt  ->   "up"

Alt+Q           ->   "Alt+Q down"
keyup of Q    ->   NOTHING IS OUTPUTTED
keyup of Alt  ->   "up"

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes Chrome  67.0.3396.87

Does this work in other browsers? Yes

Chrome version: 69.0.3472.3  Channel: canary
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: 

What a strange bug...