CLI: ionic cordova run/prepare android using wrong icon

I did create a special icon.png wich should be used when i pass a custom flag to the command line like so ionic cordova run android --device --myflag.

My custom hook sees this flag and copies the custom icon.png to resources/android, resources/ios and runs ionic cordova resources --cordova-res, which in turn generates the correct icon files within the sub-directories as i verified.

But somehow this icon is never used for the generated .apk and on my phone i still see the old icon used in my app list…

Deleting the /www directory and/or running ionic cordova prepare android --prod --myflag (which generates the correct icon, too) does not help either.

What am i missing here?

Ionic:

ionic (Ionic CLI) : 4.12.0 (C:\Users\jp\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : ionic-angular 3.9.6
@ionic/app-scripts : 3.2.3

Cordova:

cordova (Cordova CLI) : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : android 8.0.0, ios 4.5.5
Cordova Plugins : cordova-plugin-ionic-webview 1.2.1, (and 17 other plugins)

System:

Android SDK Tools : 26.1.1 (C:\Users\jp\AppData\Local\Android\Sdk)
NodeJS : v10.15.3 (C:\Program Files\nodejs\node.exe)
npm : 6.10.1
OS : Windows 10

EDIT:

Obviously it helps to remove and re-add the platform… But this is stupid, because it takes aeons of time…