In a normal browser this doens’t work either.
When I cast the default lovelace dashboard it works, so it has to be something with the Dwains Dashboard Theme. I added manual the resources of the Dwains Dashboard but it stil doesn’t work.
I suppose the dwains-flexbox-card calls the card-tools card but my knowledge stops there… This is a link for Dwains Dashboard: Dwains Lovelace Dashboard | An auto generating Home Assistant Lovelace UI dashboard for desktop, tablet and mobile by Dwains for desktop, tablet, mobile
I use this blueprint: Cast and re-cast a lovelace view to a Google Hub for casting.