Hi,
Thank for contacting us
This problem not a bug in your code
"This is a known bug with the official Chromecast JavaScript library. Instead of failing silently, it dumps these error messages in all non-Chrome browsers as well as Chrome browsers where the Chromecast extension isn't present.
The Chromecast team have indicated they won't fix this bug:
code.google.com/p/google-cast-sdk/issues/detail?id=309
"
Ok, but why he load all video at the porfolio, not only when you open lightbox - it's big problem, because when you add 40 videos there is too much errors, it's slow down loading page with portfolio.