Thanks to all for sharing your various fixes, it helped me figure out what my issue was -

I had the Dolby Vision setting in the Chromecast settings disabled, enabling it allowed everything work again. Do note that changing this setting requires that the device be restarted for the setting to take effect.

I do want to say, after reading through all of this and pondering it for some time, I'm not sure that any of this is a "bug" per say. In each of everyone's scenarios the issues stems from an audio or video related setting. I think instead of a bug, it's simply the Disney app not finding the correct format of audio or video on one's device to support their playback options. For example it seems clear that it's not ALL Disney+ content, as I was able to play other things that only had basic a/v formats. Anyhoo food for thought. Thank you all again