So shall I just post the answers here?
It only happens on PC for me as far as I know but I very rarely even use Sky Go on my phone.
PC1 OS = Windows 10 Pro x64, Browser = Firefox 43.0.2
PC2 OS = Windows 10 x64, Browser = Firefox 43.0.2
It happens on both Live & On Demand content.
Refreshing the page: It seems mostly (at least in my experience) that the error won't happen again in that particular episode for on demand content but on "live" content it happens frequently every 10-20 minutes regardless.