UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36

Steps to reproduce the problem:
1. Install Chrome Browser on Windows 10 1803 Stable
2. Configure web push notifications for:
a. Google Docs
b. Google Drive
c. Google Hangouts
d. Google Calendar
e. Google Mail
f. Google Chat
g  Google Meet
h. Slack
3. Now test with another sending emails, messages, chats, etc that will trigger web push notifications. This testing should be performed using a Google Account and while having Chrome open and actively using other tabs\websites.

I can reproduce problems with the web push notifications at-will every time.

What is the expected behavior?
Web push notifications will appear every time and play a sound (where sound is possible) without fail.

What went wrong?
After a while of actively using Chrome by switching between multiple tabs (e.g. 7), the web push notification will stop appearing and\or the sound will stop playing.

Did this work before? No 

Chrome version: 67.0.3396.87  Channel: stable
OS Version: 10.0
Flash Version: 

This is easy to reproduce. It just takes a bit of time and effort. Many others are observing the same behavior on Windows 10 1803.