Assert while playing Extreme Snowman. "block id is not in MCPE"

Verification builds: Release 980905 - 1.6.0 RC0
Summary: When playing Extreme Snowman Speed Battle I get bombarded with the below assert. "This block id is not in MCPE"

Repro Steps:

1. Download Extreme Snowman Speed Battle
2. Start game and fill a hopper.

Observed Results:

1. At seemingly random intervals the assert will pop up.
2. It doesn't seem to be happening in time with any of the redstone actions and will sometimes happen just for fun even when nothing is going on.

Expected Results:No asserts

Impact: With the amount of asserts, I am unable to properly test the map in the dev environment.

Video: https://youtu.be/ajTUb3unc6I

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Assert Failure - ctrl+C to copy this message to the clipboard!
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Assertion failed: This block id is not in MCPE
Condition is false: false
Function: ItemEntity::_validateItem in f:\darwinwork\6\s\handheld\src\common\world\entity\item\itementity.cpp @ 277

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OK
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