Strider walking slowly / choppy #305

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1. CaptainKeyboard

   added

   type: bugSomething isn't workingSomething isn't working

   on Apr 20, 2026
2. CaptainKeyboard commented on Apr 20, 2026

   

   CaptainKeyboard

   on Apr 20, 2026

   Author

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   Happens in multiple versions of NeoForge. Tested on 21.1.219 & 21.1.227
3. jasoncookie99 commented on Apr 24, 2026

   

   jasoncookie99

   on Apr 24, 2026

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   Any interm fixes for this by chance?
4. Inonedn commented on May 8, 2026

   

   Inonedn

   on May 8, 2026

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   I've been having this same issue too
5. diesaifa commented on Jul 15, 2026

   

   diesaifa

   on Jul 15, 2026

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   bumping this
6. ramen-cat-coder commented on Aug 7, 2026

   

   ramen-cat-coder

   on Aug 7, 2026

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   Same issue here on NeoForge 1.21.1
7. Kalin-moe commented on Aug 10, 2026

   

   Kalin-moe

   on Aug 10, 2026

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   I've been having this same issue too.

   sable:2.0.3
   Neoforge:21.1.243
   mc:1.21.1
8. impaladin87 commented on Sep 6, 2026

   

   impaladin87

   on Sep 6, 2026

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   having this issue too, it seems like they attempt to swim in lava rather than walking on top of it?

   sable 2.0.5
   neoforge 21.1.248
9. ThePotatoArchivist commented on Sep 6, 2026

   

   ThePotatoArchivist

   on Sep 6, 2026

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   It seems LivingEntity#canStandOnFluid gets ignored for some reason, this also breaks skis from my mod Nether Archives
10. Nobodiiiii commented on Sep 29, 2026

    

    Nobodiiiii

    on Sep 29, 2026

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    I can confirm this still occurs with Sable 2.0.5 on Minecraft 1.21.1. Vanilla striders move very slowly and stutter whenever moving through lava, regardless of how movement is initiated.

    Minimal reproduction confirmed: I reproduced the issue with only Create, Create: Aeronautics, and their required dependencies, including Sable. No unrelated mods, including Create: Biotech, are needed to trigger it.

    Likely root cause: the wrong fluid argument is checked.

    In Minecraft 1.21.1, LiquidBlock.getCollisionShape calls:

    context.canStandOnFluid(
        level.getFluidState(pos.above()),
        state.getFluidState()
    )

    The first argument is the fluid above the block; the second is the supporting fluid. Vanilla EntityCollisionContext.canStandOnFluid applies the entity's capability predicate to the second argument.

    However, Sable 2.0.5's TheFasterEntityCollisionContext checks the first argument:

    livingEntity.canStandOnFluid(fluidState)

    For a lava source block with air above it, this tests the empty fluid state rather than lava. The check returns false, causing the lava block to provide no collision support.

    Without that support, the strider can sink and repeatedly enter the buoyancy branch in vanilla Strider.floatStrider(), which halves its velocity:

    this.setDeltaMovement(
        this.getDeltaMovement().scale(0.5).add(0.0, 0.05, 0.0)
    );

    This is consistent with the reported slowdown and stuttering, and could also explain the other fluid-walking entities mentioned above.

    Suggested correction: check the supporting fluid, matching vanilla's argument contract:

    @Override
    public boolean canStandOnFluid(
            final FluidState above,
            final FluidState support) {
        return this.entity instanceof final LivingEntity livingEntity
            && livingEntity.canStandOnFluid(support)
            && !above.getType().isSame(support.getType());
    }

    The minimal-environment reproduction is confirmed, and the argument mismatch is verified against the linked 2.0.5 source. The proposed correction has not yet been runtime-tested.