Review the growth conditions
Compare light, root conditions and recent moves before treating one smaller leaf as a fertilizer shortage. Plants can respond to changes in the environment, and old nursery leaves may have developed elsewhere.
Watch several new leaves and inspect the growing point. Avoid increasing water and feed together without checking the root ball. Keep useful foliage while the pattern becomes clearer.
FAQ
Should the small leaf be removed?
Not merely because it differs in size; assess its condition and function.