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  1. Minecraft: Java Edition
  2. MC-142520

Mob physics break upon loading a world in 19w03a



    • Type: Bug
    • Status: Resolved
    • Resolution: Fixed
    • Affects Version/s: Minecraft 19w03a
    • Fix Version/s: Minecraft 19w03b
    • Labels:
    • Environment:
      Java version is up to date, 1.8.0_171. Windows 10, multi-core laptop. DoMobSpawning had been previously disabled, but was enabled while testing this. A Superflat world 
    • Confirmation Status:


      Upon loading a world that has multiple entities confined in a small space or up against a wall while affected by a water current especially a 1x1 area, the entities will phase through the terrain, escaping captivity and creating a huge mess. They do not seem to fall through floors, but will go straight through multiple-block-thick walls. The force that propels them seems to be mob overlap repulsion, but it can also occur with water, allowing this bug to affect a single mob with nothing (but walls) nearby.

      If I had to guess, the issue is that mobs begin moving before terrain physics are loaded properly - when you load into a world, you can catch a solid five seconds in which chickens flap their wings as if they were airborne. For some reason, this does not affect the player at all.


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          Jacob Andrew Jagiella
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          Jacob Andrew Jagiella

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              • Assignee:
                The_Endgineer Jacob Andrew Jagiella
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                • Created: