Since update 18.104.22.1687 there are now two cast buttons which appear next to the fullscreen button on the top-right of the player.
These two buttons also appear in the controlbar to the right of the quality settings button. So there are four cast buttons in total.
I checked on foliovision.com and the video on your homepage shows four cast buttons as well so it’s not specific to my setup.
I love FV 7. Keep up the good work.