Android webview crash "Fatal signal 5 (SIGTRAP)"

Try to override the back navigation functionality and close the popup yourself.

You don't need to handle all the stack navigation logic, just have a state when you are showing this popup. Apply your own navigation logic(like manually closing the popup).

void onBackPressed(){
    if(isTheBuggyPopupIsOn){
        closeTheBuggyPopup();
    }
    else{
        super.onBackPressed();
    }
}