TPS55010: TPS55010 heat up when there is no load

Part Number: TPS55010

Dear TI team:
    My customer used TPS55010 for 5V to 5V isolate application, they found TPS55010 heat up when there is no load, please help to check what is the problem? Thanks!

    Is it because IC thermo pad is not connected to the ground PIN of 55010, and there is too little ground on the top layer?

    Thanks!

 Regards!

 Eric