Tyrannosaurus drinking legs twitch on slope

Tyrannosaurus legs twitch when drinking water while standing on sloped terrain

When the Tyrannosaurus stands on an inclined / sloped shore and performs the drinking water animation, its feet keep shaking and twitching continuously. The drinking thirst progress works normally, only the leg‑IK animation is glitching. Please see the attached video and screenshots for details.

When drinking on a sloped surface, the dinosaur's legs should stay stable without shaking or twitching. Leg IK should adapt properly to sloped ground.