I was able to resolve this by modifying my Aspect as below:

 @AfterReturning(value="pointCut()",returning = "respValue")
    public void logResponse(JoinPoint joinPoint, Object respValue) throws Exception {
        Flux<Object> resp = respValue instanceof Flux ? (Flux<Object>) respValue : Flux.just(respValue);
          resp.doOnNext(returnValue ->{
          log.info("response :: {}",respValue);
        }).subscribe();
}