"Single-tick ground-check flicker machine-guns the landing squash"

The character's landing squash/stretch or landing particle effect fires repeatedly while running at speed across terrain. The character appears to "bounce" or stutter visually even though the controller logic is working correctly and the character never actually leaves the ground in a meaningful way.

A trace-based ground controller that fails a single GroundCheck (e.g., crossing a terrain seam or a small step) flips the state to Air and runs the Air tick in the same fixed step. On the very next tick, the GroundCheck passes again, flipping back to Ground and pulsing JustLanded.

This Ground → Air → Ground cycle completes in one or two fixed ticks — far too fast for the player to perceive as airtime — but the visual system sees JustLanded == true and fires the full landing effect. At speed, every seam or micro-step triggers this, machine-gunning the squash animation.

Fix in the visual layer only — leave the controller state machine identical. Track continuous air time and require a minimum threshold before treating a JustLanded as a real landing:

// In your visual/animation controller
private float _airTime;

void OnFixedUpdate()
{
    if (Controller.IsGrounded)
    {
        bool realLanding = Controller.JustLanded && _airTime > 0.1f;
        _airTime = 0f;

        if (realLanding)
        {
            PlayLandSquash();
        }
    }
    else
    {
        _airTime += Time.Delta;
    }
}

Capture _airTime before resetting it — JustLanded pulses on the frame the state is already back to Ground, so _airTime must still hold the accumulated value at that point.

The controller is doing its job correctly — it reports ground contact truthfully. The problem is that the visual feedback doesn't distinguish between "was genuinely airborne and landed" and "flickered through a one-tick gap." A 0.1-second minimum air-time threshold filters out the micro-flickers without affecting real jumps or falls, where the character is airborne for significantly longer.