Unity2021.2.18 cant destroy objects instantiated as children of parent object marked as "DontSave"

Bug report: https://fogbugz.unity3d.com/default.asp?1420510_6cr8s3dj1err2op5
Issue tracker: Pending...

Unity 2021.2.18 can't destroy objects which are instantiated as children of the parent object which is marked as "HideFlags.DontSave".

This was working fine before 2021.2.x.

Repro steps:
1. Open Test scene.
2. See that there is no Cube object in the scene view.
3. Select "TestScript" object in Test scene.
4. Enable "Test" component on that object. (This script runs in editor)...

Unity2021.2.18 cant destroy objects instantiated as children of parent object marked as "DontSave"