What is the Self-energy of a Grounded Isolated Spherical Conductor?

I came across this Scenario where you had to calculate the Self-energy of a Grounded Spherical Conductor and it was given as Non-zero and the General Definition of Self-energy of a Metallic Sphere was given. My intuition was that Self-energy of a Grounded Metallic Sphere would be zero as All the charges forming it are brought from Infinity to a system with zero potential. Can someone explain why my intuition is wrong?