I think this is actually a bug. I have 120mps download and have never had an issue streaming at the highest res until the past few days. Now it takes 4-5 mins to load each video then plays 20secs and buffers, plays 10 secs buffers, continues.
Even downloading a video now it's going max 15-17kbps. It's telling me it will take 3 days to download one film.
I've tested on my phone in both Wi-Fi and cellular data. I'm using the SLR app on Daydream.