Bug Report
Ionic version:

[x] 4.10.0

I'v even post a bug to report the same isssue in ios: #19170 (comment), which is resolved in a dev patch.

Current behavior:
However, when update to latest 4.10.0, the same issue raised again. This time is in android.
Sometimes, page will flash when navigate back, not always.

I test it in android device and emulator, android 8 and 9.

Degrade @ionic/angular to 4.9.0-dev.201908231742.f2cfdf14.7.4, it will disappear.

Expected behavior:

Steps to reproduce:

Use navigation to push a page, then close it use back-button. sometimes a flash will appear.

Related code:
Use <ion-back-button></ion-back-button> to navigate back.
Other information:

I take a video to watch what happens. when slow down the video frame, I can see that when click back-button, the current page transit to dismiss, then suddenly appear half a second, then dismiss again, so in normal speed, we can see a flash.
Ionic info:

Ionic CLI : 5.4.1
Ionic Framework : @ionic/angular 4.10.0
@angular-devkit/build-angular : 0.803.5
@angular-devkit/schematics : 8.3.5
@angular/cli : 8.3.5
@ionic/angular-toolkit : 2.0.0