On occasion, all grass and stone blocks will just disappear. I can still walk on them, but basically everything except wood and water is invisible. I first started having this problem in a modded world. Which I thought was normal, or to be expected because I was running a lot of mods. But then it happened in a vanilla survival world. When it had happened both times I had been playing in those worlds for several weeks and thought the engine might just get tired at that point. But then it happened in a creative world, only a few days old. Also, it's happened in a swamp biome all three times. I can fix it easily with F3+A, but I'm just curious as to how and why this happens. Any thoughts?

On occasion, all grass and stone blocks will just disappear. I can still walk on them, but basically everything except wood and water is invisible. I first started having this problem in a modded world. Which I thought was normal, or to be expected because I was running a lot of mods. 

But then it happened in a vanilla survival world. When it had happened both times I had been playing in those worlds for several weeks and thought the engine might just get tired at that point. But then it happened in a creative world, only a few days old. Also, it's happened in a swamp biome all three times. 

I can fix it easily with F3+A, but I'm just curious as to how and why this happens. Any thoughts?