Fill commands can crash worlds, likely based on their version of origin

Partner Rank: 3

Partner Team Reporting: Noxcrew

Verification builds and Platforms: 

minecraft_uwp_renderdragon_x64_win10_5080499_release

Summary:

Using the fill command causes a crash under specific circumstances. I won't be able to track down the specific cause, but I found a consistent way to replicate the circumstance, and I have some thoughts on things that may be related.

We recently found an issue with boats having no gravity on templates created before a certain version (MCM-1265). This seems to be similar behavior, in the sense that the issue is only happening in older templates. We've only personally seen the issue in the scenario listed below, but a community member found the following bugs which seem to be the same type of issue:

https://bugs.mojang.com/browse/MCPE-104004
https://bugs.mojang.com/browse/MCPE-102908

The second bug was marked as unable to repro, so I'm filing this bug with a very specific set of steps which we've confirmed reproduce the issue.

Impact:
Doesn't affect our workflow or future maps, but this sort of inconsistency in old maps makes players think we're doing something wrong in the maps causing them to crash, when ultimately it's a vanilla issue of some sort. 

Repro Steps:

1. Purchase "City Living" by Noxcrew from the Marketplace
2. Load into the world
3. Type: /fill 537 42 1033 546 42 1114
4. Notice the game crashes after typing the last coordinate and hitting space
5. Download the "City Living No Bug" world (@greggo will have it on slack)
6. Load into the world
7. Type: /fill 537 42 1033 546 42 1114
8. Notice the game does not crash after typing the space. This proves the issue is somewhere either in Marketplace encryption, or back compat support with older templates.

Observed Results:

The game crashes (as in step 4)

Expected Results:
The game should not crash (as in step 8)

Screenshots/Videos attached:

No screenshots/videos needed.