Steps to reproduce the problem:
1. make page with notifications (e.g. https://github.com/kenng/firebase-push-notification-demo)
2. subscribe notifications on phone in chrome on android
3. make phone offline (fly mode)
4. send 10 notifications to device
5. make phone online

What is the expected behavior?
I should get 10 notifications

What went wrong?
I got about 7 notifications only

Did this work before? No 

Does this work in other browsers? Yes

Chrome version: 71.0.3578.99  Channel: stable
OS Version: 8.0.0
Flash Version: 

To check number of notification we use console.log in service worker and chrome://gcm-internals/.
In android firefox is no problem.