JS Fetch Catch from Spring Controller Exception not executed due to Spring Boot's BasicControllerException JSON output

Question

My Spring Boot Controller throws an Exception, but on the JS Fetch side, the flow does not go into catch(err). Rather, it goes into the then() as below, which is incorrect.

@PostMapping(path = "/submit")
public void submit(@RequestBody CaseInquiry caseInquiry) throws Exception {
    
    // test
    throw new Exception("test");
    
}

JS Fetch:

const submit = () => {
        fetch("/app/submit", {
            method: "POST", 
            body: JSON.stringify(Object.fromEntries(valueMap)),
            headers: {
                "Content-type": "application/json; charset=UTF-8"
            }
        })
        .then(response => response.text())
        .then(result => { 
            alert('Success'); // Comes here (incorrectly with JSON string)
        }).catch(error => {
            alert('Error: ' + error); // Does not come here
        });
    }
}

The then() result is

'{"timestamp":"2023-08-21T13:07:06.832+00:00","status":500,"error":"Internal Server Error","path":"/app/submit"}'

I found in this thread that this JSON output comes from Spring Boot's BasicErrorController.

It's used as a fallback when your application hasn't handled an exception using Spring MVC (with an ExceptionHandler or ControllerAdvice, for example) or a container error page.

So is there a way for me in Spring Boot to allow exceptions to propagate so that I catch them with catch() in the JS Fetch?