If you hold a Turtle's favorite food, which is Seagrass, it will not follow you unlike other animals that follow you when you're holding their favorite food.

Chickens follow you when you're holding seeds

Sheeps follow you when you're holding wheat

Turtles do not follow you when you're holding Seagrass

Check out my YouTube showing me reproducing this bug! Turtles do not follow you when you're holding their favorite food, Seagrass.