After flying around in spectator mode for a while, the game will crash occasionally when the player crosses the border between non-transparent blocks and air blocks.

Examples of this:

-Simply going below the surface of the ground
-Emerging back to the surface
-Entering cave (From the side)
-Leaving cave (Through a wall)

How to reproduce:

As to how to actually reproduce this bug I am uncertain about, but flying around in spectator mode for a while on a default world may or may not work. This bug does seem to happen only occasionally, after around 20 minutes of me going in and out of spectator, albeit very annoying. (Sorry I can't be more descriptive here)

Some things that might increase chances of this crash occurring:

-Try purposely flying bellow and back above the ground
-Try purposely flying in and out of caves

Related Issues: (Why I don't think this should be marked as a duplicate)

I found a bug report titled "Crash: Rendering entity in world 'java.lang.ClassCastException: adm cannot be cast to adu" which I looked at, although thought the bug I was experiencing, although related, is probably not be caused by the same thing. I think this due to the fact the block id system has been overhauled in the last few snapshots, and the attached bug reports seem to indicate this as true.

Link: MC-111464

Possible Causes: (Only my speculation)

I think this bug may be caused due to the game trying to look up some properties of an air block that it is trying to render. Since air doesn't have any properties, this is likely the cause of the bug, as there is no problem when flying through a set of solid blocks, but only, as far as I've noticed, when the player either enters or leaves a region of solid blocks.

This may or may not apply to glass, which I haven't tested yet due to the unpredictableness of the bug. I don't think it would, as I think it is more to do with block states, as opposed to whether or not a block is transparent or not.

Liquids also seem to not be an issue as far as I can see.

Attached Files:

11 Bug reports I've received over the course of the past few days. All seem to be caused by this same issue. I've attached 11 of them so that I can demonstrate the frequency of the crashes. Sometimes they will happen a few times over the course of 10 minutes, while other times it will take up to half an hour for it to crash.