Approval rule for AOR but only need one to approve

Hi all. I have a business requirement to configure the Terminate Emp flow so that certain 'then' statements will go to an AOR (HRBPs, in this case), but approval is only needed for one. I added the below:

This only sent it to the first HRBP and no others. The above worked great for other flows where just an FYI is needed.

Then, I clicked Edit Approval Participants and chose Parallel and First responder wins, as seen below. Then, it goes to all, but after one approves it, the Approve button is still available for the others in the AOR, and they get an error when trying to click on it.