As I've said Screen mirroring/casting on all Samsungs Tabs are disabled by default, well those that are running L 5.0.0. any way. I did some testing yesterday, I cast my Tab Pro 12.2 to my TV and let it stream for 30mins or so. I stopped the cast and loaded Sky Go on my Tab and started to watch cricket. I never had any problems at all.
Having said that I did the same on my Lenovo YT2 Pro 13.3 but this time after removing the cast I was unable to stream Sky Go on my Tab due to it not allowing Miracast, which is odd as MiraCast is not on my Tab.
I got it to work in the end by disconnecting my TV's Wi-Fi and Sky Go played on my Tab. Next I connected my TV's Wi-Fi back up and used YouTube on it, This time when I started Sky Go it worked np at all. I can only think that either the TV or my Tab retain this information while connected to my Wi-Fi