I just dug up and transplanted a baby elephant ear in a pot. Its small leaves on the bottom are yellow

Question

The leaves at the bottom are dead.

Answer 1

Yellow leaves could indicate watering issues; too much or too little.
It could also be disease, pests or lack of nutrients.
These articles will help you review the care needed.

https://www.gardeningknowhow.com/ornamental/bulbs/elephant-ear/growing-elephant-ears-indoors.htm
https://www.gardeningknowhow.com/ornamental/bulbs/elephant-ear/elephant-ears-taking-over.htm