I can think of 2 possible reasons if I may:

1. Dialogs do not inherit insets automatically. Unlike full-screen composables, dialogs do not automatically respect safeContentPadding(). You might need to manually apply WindowInsets. Could you log the insets inside the dialog to confirm/disprove this?

2. Scaffold inside a Dialog behaves differently than in a full screen Composable. The Scaffold insets inside a dialog do not behave as expected compared to a normal Composable, I also had the experience.

If it doesn't help, then I think it would come to different implementations of AOSP used by the manufacturers.