Sprite Skin bone assignments are lost when Auto Rebind is enabled on sprites with disconnected bone chains

Steps to reproduce:

1. Open the attached project “IN-141601”
2. Open “bug_Prefab” in Prefab Mode
3. In the Inspector, on the “Sprite Skin” component, click “Create Bones”
4. Enable “Auto Rebind”
5. Observe the result

Actual result: Some bone references become unassigned and rebind warnings are logged
Expected result: All bones remain assigned

Reproducible with: 9.0.0-pre.3 (2023.1.0a1), 10.2.2 (6000.0.74f1), 13.0.4 (6000.3.14f1), 14.0.3 (6000.4.6f1), 15.0.3 (6000.5.0b7, 6000.6.0a4)

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Note: The first line of the warning “Rebind failed for test1_0. Could not find all bones required by the Sprite: test1_0.
UnityEditor.GUIView:ProcessEvent (UnityEngine.EntityId,intptr,bool&)”