Commented: Sugar Apple Helpit happen to me on a lemon tree and i was told some tiny spiders do this to the new plant leaf and cause this deformation try to spray with some insecticide may it may help
Commented: What kind of plant is this? Dieffenbachia?yes it is ðÂÂÂ
they do love bright light which is well provided as per you photo
i saw people support them with sticks to keep them upright !