I had a case in which my react app calls the same api endpoint twice. The call is wrapped inside the useEffect hook. At first, I thought the page was rendered twice, but that was not the case.

useEffect(() => {
  callEndpoint();
}, []);

After further investigation, apparently the useEffect is executed twice even though the trigger is an empty array. I found out later on that it is due to React.StrictMode. In my App.tsx:

<React.StrictMode>
  <App />
</React.StrictMode>

Removing it removed the duplicate execution.

//<React.StrictMode>
  <App />
//</React.StrictMode>