I reported this problem yesterday, and it was brushed off as a duplicate, but this is not for a mulitplayer server or singleplayer world where I can easily erase cache data myself. 

Everything was normal at first, but all of a sudden the light sources at my underground base stopped emiting light. Turning the whole area dark, and I get mob spawns everywhere. 

I use different light sources (torches, glowstone, end rods), and the bug effects all of them. If I update the block next to the light source it starts to emit light again, but as soon as I leave the area and come back.

This seems to be a common problem. It happens in some chuncks, but how do I fix this on a REALMS server? 

What I expected to happen was...:
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What actually happened was...:
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