Steps to reproduce:

1. Create a new project using 3D universal template
2. Enable “Use new Hierarchy window” in Edit -> Preferences -> General
3. Right-click in the Hierarchy columns and add "Tag"
4. Create a few empty GameObjects in the Hierarchy
5. Multi-select created GameObjects
6. In the Inspector, click on Tags dropdown and select "Add Tag..."
7. Click "+" button and create a new tag
8. Repeat 5th step
9. In the Inspector, click on Tags dropdown and select the newly created tag
10. Observe the Tag Column in the Hierarchy

Actual results:  Selected GameObjects remain "Untagged"

Expected results: Selected GameObjects have the selected Tag shown in Hierarchy

Reproducible with versions: 6000.5.0a6, 6000.3.8f1, 6000.4.0b8 

Can’t test with versions: 6000.0.67f1 

Tested on (OS): Windows 11

Notes:

• The tag is added but not displayed in the Hierarchy
• Trying CTRL+Z after reproduction sometimes show one or other GameObject with the correct tag