Could you inform us as to what known issue is being worked on? If it helps, I did some of my own
analysis during the brief time when Chromecast was enabled on both my S7 and an S8 I had on hand. The two issues I discovered were related to audio and heat output.
For the latter issue, someone else commented that being able to choose a lower streaming quality (e.g. 480p15fps) would help a lot.
S7 Exynos Nougat. 2017 Gear VR. Public test channel.