Use folio-testing or folio-snapshot.
Open the modal to create a new or edit an existing instance, holding or item.
Set the focus into the first focusable element.
Now press Shift + Tab (one time or repeatedly).
Expected: The focus wraps around and moves into the last focusable element.
Actual: The focus disappears.

Note: The other direction works: Pressing Tab allows to wrap around from the last focusable element into the first focusable element.