Issue in hardware back button /Ionic V4

I’ve navigated every page,and made use of hardware back button for coming to previous page every thing is working fine only issue is while opening the app the before making any changes on pressing the back button the app terminates without confirmation but the confirmation appears when any change is done


I’ve used android version (OREO)8 in this application it shows these error on degrading the version to (LOLLIPOP) 5 its working perfectly without any issues.

Any help from the Ionic Family