Hello, neonatal jaundice is of two types, physiological (due to immature liver), starts from 3-4days of life and comes down by 2 weeks, only needs phototherapy to recover faster. It doesn't come again, while pathological jaundice can occur at any age, cause may infections, inflammatory, surgical causes, hematological, depending on cause can occur at any age. Nothing to worry, it's usually rare,, maintaining Gud hygiene is enough to prevent infection.