This is my setup. In 4.19 this made the eyes slightly “dart” around because the focus was slightly changing position every 0.5-2 seconds. Making eye movement very realistic. Now the behavior is different. The character seems to still focus, but the movement has changed in 4.20, ignoring the subtle changes, making it less realistic.
The relative locations will probably make little sense, this is because my rig is upscaled by 100.