Spotify web, chrome, and chromecast

[kite11]

For some reason casting from open.spotify.com requires clicking output source more than once -- usually twice. Other sources work on first intention. On first try the chromecast connection sound is heard but sound still comes out of computer. It takes multiple, usually two times for sound to really output to external device.

What is the cause and can this be fixed?

Mac

Chrome latest version [I believe this has persisted through multiple versions of Chrome.]