mobs sprinting in 1.12.2

When I was playing on a survival 1.12.2 world (only installed optifine) When a mob targeted me that was relatively far away it sprinted towards me as if it was springing with speed 2. When the mob got within about 5 blocks of me it stop sprinting and just acted regular, i saw this happen with a few creepers in a cave, then zombies outside at night. I didn't see this but when I searched for it online or on this website.