When more than one accordion exists on one page ( ie more than one component each one having it own accordion), [multiple]="false" does not prevent multiple accordion items to be opened at the same time on the first accordion while toggling open and close on the second accordion does not work as supposed to be : toggle open the first time does not open the item but the chevron changes to open state, toggling again the first item sets the chevron to close state but the item opens.