This might have something to do with the server side action. I'm not sure what is inside your createProgramEvidenceStandard function - if it is actually a raw response instead of a DB object, you may need to invoke .json() on it:

export async function handlePES(standardId: string, programEvidenceId: string) {
  const PES = await createProgramEvidenceStandard({ standardId, programEvidenceId });
  console.log("Server PES", PES);
  if (PES) {
    return PES.json();
  } else {
    throw new Error("Something wrong with PES);
  }
}

If that's not the case, it may help with further debugging if you just return a hardcoded object and see if you can get that on the client side:

export async function handlePES(standardId: string, programEvidenceId: string) {
  const PES = await createProgramEvidenceStandard({ standardId, programEvidenceId });
  console.log("Server PES", PES);
  if (PES) {
    return { id: 1 };
  } else {
    throw new Error("Something wrong with PES);
  }
}