I'm having the same issues at the cottage and this is a brand new Chromecast. I can cast from any other app on my phone or laptop but not from Ignite...ridiculous!
I had a tv in the kitchen and one in the living room that I could watch at the same time from the kitchen table with no glitching on cable. Now I have ignite and there is a 2 second delay...so aggravating!!! Makes me regret my decision to change!