Not sure why cast to player boolean isn't working

I have another blueprint casting to my player blueprint that changes a bool to false when the code finishes, but nothing is happening and I’m not sure why. The bool variable is an editable instance.

Set a breakpoint on the Set Boolean node (or, ideally, the first node after the event source.)
(In blueprint, click the node, press F9, to set a breakpoint)
Then trigger the action.

If the game stops, step through each node with F10, to see what it does.
If the game doesn’t stop, then the event isn’t triggered at all.