Example URL:
http://codepen.io/arickle/full/PNWJwy

Steps to reproduce the problem:
1. Visit that CodePen on an Android Device with Chrome
2. Tap button to open up popup
3. Fling scroll to the bottom of popup
4. Try to tap on a button to close the popup
5. Observe that the first tap does nothing, but a second tap will work

What is the expected behavior?
First tap should work.

What went wrong?
It seems like the fixed element is losing focus or something when you fling scroll and hit the bottom (or top) of the overflow. Tapping once gets focus again, tapping a second time will actually tap the button.

In debug mode on a desktop, flinging to the bottom and then clicking the button from desktop does not reproduce this issue. Only the tap on the device.

I've tested this on a couple Nexus 5X's and a Samsung Galaxy Note 4. The Note 4 had "CM Browser" on it. Problem does not happen in that browser.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes 

Chrome version: 49.0.2623.91  Channel: stable
OS Version: 6.0.1
Flash Version: 

Wish I knew if it worked before. I may just not have noticed. Also, it has to be a fling scroll. If you just scroll normally and inch your way to the bottom, you cannot reproduce the issue.