Sorry! This is an issue we are aware of and are currently working on a fix for.
The current workaround is just to close the chrome window and open a new one or to close the movie with the “X” before it ends (i.e. when the credits are going on). Another is to just refresh and un-sync and then re-sync cast.
As well, if you manually go to next video using the arrow next to the play button, the loading should work just fine. Please let me know if you are able to find any additional workarounds - hopefully we can get it back to normal soon!