Flipping Cards behave individually, but are slow to change en masse

The prototype I’m working on contains 30 cards (2-state DP).
Each card is a Master.
Each card flips from state 1 to 2 and from State 2 to 1 on click. This performs as expected.
There’s a control on the page that flips all of the cards at one time (On Click, change state for a, b, c, d, etc.).
For some reason there’s a lag of about 5 secs after the page level control is clicked then the cards flip.
Any thoughts?