Your plant appears to be situated too deep in the pot.

If the small leaves you're noticing are on offsets appearing at the base of the plant, it might be a genetic trait. Many plants grow successively larger leaves as branches or stems extend. Witness the Ficus genus.

BTW - Low light levels produce long internodes and an increase in leaf size, as plants are programmed to maximize the photosynthesizing surface under these conditions. High light produces short internodes and smaller leaf sizes as the plant has less difficulty getting the light it needs to carry on with all that they do.

Al