Kotlin: Spring ExceptionHandler Not Working When Validating RequestBody

Question

It seems I cannot get my @ControllerAdvice to work with Kotlin POJOs. Note, it works when I throw an exception and with path params but doesn't work when validating the body of a request.

ControllerAdvice

@ControllerAdvice
class ExceptionAdvice : ResponseEntityExceptionHandler() {
    companion object {
        private val log = LoggerFactory.getLogger(this::class.java.name)
    }

    @ResponseBody
    @ExceptionHandler(CustomException::class)
    fun onException(exception: CustomException): ResponseEntity<CustomError> {
        log.error(Generic.EXCEPTION_PROVIDER_LOG, exception.message, exception.errorType, exception.errorType.httpStatus)

        return ResponseEntity(
            CustomError(exception.errorType.error, exception.errorType.name), exception.errorType.httpStatus
        )
    }

    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(ConstraintViolationException::class)
    fun onValidationFail(exception: ConstraintViolationException): CustomError {
        log.error("Request did not conform to spec. Constraints violated: {}", exception.toString())

        return CustomError(ErrorType.G001.error, ErrorType.G001.name)
    }
}

Controller

@RestController
@RequestMapping(produces = ["application/json; charset=UTF-8"])
@Validated
class StoreDataController {
    companion object {
        private val log = LoggerFactory.getLogger(this::class.java.name)
    }

    @Autowired
    private lateinit var service: Service

    @PostMapping("/store-data")
    @Throws(CustomException::class)
    fun storeData(@Valid @RequestBody data: Data): ResponseEntity<String> {
        return ResponseEntity.ok(data.title)
    }
}

Body

data class Data(
    @field:Pattern(regexp = "[\\w\\d ]+", message = "Title can only use letters, numbers and spaces") var title: String
)

What Gets Returned

{
    "type": "about:blank",
    "title": "Bad Request",
    "status": 400,
    "detail": "Invalid request content.",
    "instance": "/api/v1/store-data"
}

What should happen is the ControllerAdvice should intercept the error using the @ExceptionHandler(ConstraintViolationException::class) annotation. Do I need to do anything else here?