Quick answer: Unity Mecanim 1D blend tree snapping to closest sample at speed > max sample? Default extrapolation is clamp - set Compute Thresholds to Velocity and add a higher sample.
Run-cycle blend tree samples at 0/3/6 speed. Player sprints at 8 m/s; animation snaps to run-6 sample but feels jerky.
Add extreme samples
Authoring step: include 0/3/6/9 m/s. Blend covers full range; extrapolation is rare.
Set extrapolation behavior
Blend Tree inspector > Extrapolation. Linear extrapolation extends the trend; less jarring than clamp.
Or use 2D Cartesian blend
For direction-aware blends, 2D handles edge cases better. Migrate if 1D feels insufficient.
“Blend trees interpolate between samples. The values outside samples have to be handled deliberately.”
Sample your blend trees at gameplay extremes. Authoring at typical values misses the extreme-value bugs.