My son on his Android tablet was jumping down some stairs in the Nether in my Realms world when it froze on him. I walked near him playing in Win10 and it then froze for me also. I've tried exiting and re-entering multiple times, and it typically freezes during the Building Terrain stage of loading. I've tried swapping the Realm over to Creative to no effect, and back again.

I'm not sure where to find crash logs, or I'd attach one.