Environment

Vuetify Version: 3.10.2
Vue Version: 3.5.21
OS: Linux

Steps to reproduce

1. Click on "expand all" button
2. The "expanded" model contains the items, but no rows are actually expanded in the table
3. Click on the expand button on the first row
4. All rows are now expanded and the model contains [null]
5. Click on the collapse button on the first row
6. All rows are now collapsed and the model is again empty []

Expected Behavior

When clicking expand all button, all rows should be expanded. When clicking expand none button, all rows should be colapsed. When clicking on individual rows to expand / collapse, only those rows are expanded / collapsed

Actual Behavior

Expand all / Expand none does nothing, although the expanded model is "correctly" filled-in / emptied.
Clicking on a single row to expand, expands all rows, while the model contains [null].
Clicking on a single expanded row to collapse, collapses all rows and empties the expanded model.

Reproduction Link

https://play.vuetifyjs.com/#...

Other comments

Changing vuetify to version 3.10.0 (or any previous) makes the demo work correctly and as expected.

Images