I've noticed in my realm that i have been playing in for a little bit now that i have been having some lighting issues, where i will get on and torches will only light up the chunk they are in or a decreased area and will cut off suddenly. It might be because my connection, I don't think its my connection. It might also be server load because i have a ton of chickens in one little space to make eggs, I'm not sure but it fixes with more torches, but still its there.