Dingbatt: Having re-read your first post again. Can you just confirm it is crashing Android on your TV when you play NF or YT on your PS4? Or is it crashing the PS4? (Both Sony products, but probably just a coincidence). I'm assuming it's just the TV.
Even on my LG TV (running WebOS), the Netflix app doesn't play nice all the time. After a while of watching it ignores IR commands and will only respond to the 'Magic Remote' wireless signals. So maybe the developers of the Netflix apps need to have a look at their coding. Might be worth dropping a line to the developers of the Netflix App for Android if that ends up being the source of the problem.
Even though it comes with the TV, and may even be baked into OS, Sony will probably say it's not their problem if it is the app.
It's crashing the TV. The TV boots back up as if a factory reset has been done, but I dont lose any settings.
I haven't had a chance to test the TV this weekend so I haven't been able to do some of the suggestions on here.