Unfurled Monstera Leaf. If the leaves of your Monstera arent splitting it usually comes down to two factors. Keep in mind that after a leaf develops it will not change.
For more info read 4 Signs Your Monstera Is Over-Watered here. The plant has pests. As the plant matures the newer leaves will slowly have more and more fenestrations.
If your Mini Monstera features curling leaves this could be due to too low humidity.
Be sure to read my blog post on underwatering and overwatering to learn how to properly water a houseplant. It also is a great ideal starter house plant for the beginner. Will Monstera leaves split after unfurling. What should I do here.