[MCM-556] [CRITICAL LIVE] Crazy Town permanently freezes on a black screen at the end of the Mayor's task

Partner Rank:

Partner Team Reporting:

Everbloom Studios

Verification builds and Platforms:

1.9 Nintendo Switch (Build 1627792)

1.9 Android LGTP450 (Build 1658977)

Summary:

NOTE: Not 100% reproducible but quite frequent.

At the end of Crazy Town, a recently released piece of content, when you finish the Mayor's task, he walks outside and your screen turns black for about a second. After that, it is supposed to start a cutscene. However, on some devices, the auto-save icon appears in the top right and then the game completely freezes. It does not accept any user input and can only be shut down by closing the software followed by the "Software closed due to an error" message. If you rejoin the world after this "Force quit and relaunch" then you sit at the bottom of the credits in the dark unable to progress.

Impact:

Content cannot be completed. Breaks minecraft. Severe user impact. Although it is at the end of the content, the people who worked on it do not get proper credit. The finale is not witnessed. The bonus content can not be accessed. Not only breaks our content but Minecraft as well.

Repro Steps:

Download the content "Crazy Town" from the marketplace
Enable cheats
Open the world
Run the following command: /clone 7 3 496 7 3 496 7 13 496 replace move
Run the following command: /tp -828 11 74
Enter the building and then the Mayor's office to the right.
Allow him to finish his speech and follow him into the next room.
Wait until you receive a colored paper item in your inventory.
Run the following command: /scoreboard players set @e[type=zombie_villager] mayorTask 7
Wait for the Mayor to exit and the screen to turn black.
Either observe the issue, or if the cutscene begins, repeat the steps again.

Observed Results:

Content freezes. Unable to do anything but quit.

Expected Results:

Cutscene starts mayor gives his speech. Then blackout then BONUS CONTENT UNLOCKED message in chat and then tped to credits with night vision. After the credits you are returned to the lobby.

Regression Builds:

Unknown.

Notes:

Cannot reproduce 100% of the time. But reproducible a significant portion of the time.

Does not occur on Windows 10 as far as I can tell. Also does not occur on iPhone X.

IMPORTANT:

The command line starting at 36 1 438 runs successfully. This tests to see if the "finale tickingarea" is loaded and then once it is, it sets a redstone block in there to begin the finale. In other words, once it verifies that the finale redstone is loaded, it places a redstone block at 1 1 465.
This is the PRECISE MOMENT that the bugs occurs. This is verifiable by doing a test where instead of going through the repro steps, you just create the finale tickingarea and then do /setblock 1 1 465 redstone_block. Doing that succeeds every time. Therefore, the bug precisely originates from attempting to set a redstone block in the newly loaded chunk nearby as described above.