Ionicons 4.4.3 not showing on Android

after upgrading ionicons from 4.4.2 to 4.4.3 they are not longer displayed on Android.
I can see these icons if I use the browser (ionic serve -lcs) and if I use the simulator “Ionic DevApp”.
But if i create a package with:
ionic cordova build android --prod
and I install the app on Android I can’t see them.
It seems thay are not present in the app.

If I downgrade ionicons from 4.4.3 to 4.4.2 they are displayed again.
I’m using ionic 4.1.2.

Which could be the problem?