To reproduce: lure a animal with their favorite food (carrot for pigs, wheat for cows, etc.) while behind a dunes plant (the animal must be in front of you). You can see that the animal will pathfind through the plant, instead of turning around to reach you. This seems to affects all mobs, including modded ones, such as Roadrunners and Rattlesnakes from Alexsmobs, wich do spawn in the Dunes, since it's classified as a desert biome.