Also, I'm not sure who raised the questions about the behavior of "Expand all cards" , but it should work like this:

“Dynamic toggle text will update based on the state of the expandable cards.

The text should read:
'Expand all cards' when all or some cards are collapsed; and
'Collapse all cards' when all cards are expanded.

When there are some already expanded, clicking on 'Expand all cards' will expand the rest of them.”