auto purple kush coco 4x4

hi guys i just started an auto purple kush grow in coco (day 18). im using GH nutes @ 400ppm and ph @ 5.9 with a 600w HID light 8n a 4x4 tent. i noticed that at the end of one of the fan leaves a branch started growing in place of a finger from the fan leaf. just wanted to see what you guys...