@JSONField的format时间格式化配置会被全局配置覆盖

@JSONField(format="yyyy-MM-dd HH:mm:ss")
private Date date;

xml中

<mvc:annotation-driven conversion-service="conversionService">
        <mvc:message-converters register-defaults="true">        
	    <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
                <property name="supportedMediaTypes" value="application/json;charset=UTF-8" />
                <property name="fastJsonConfig">
                    <bean
                        class="com.alibaba.fastjson.support.config.FastJsonConfig">
                        <property name="serializerFeatures">
                            <array>
                                <value>WriteMapNullValue</value>
                                <value>WriteDateUseDateFormat</value>
                                <value>DisableCircularReferenceDetect
                                </value>
                                <value>IgnoreNonFieldGetter</value>
                            </array>
                        </property>
                        <property name="dateFormat" value="yyyy-MM-dd" /><!--会覆盖@JSONField的format yyyy-MM-dd HH:mm:ss-->
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

跟踪源码发现在转换javabean的时候FieldSerializer会调用到JSONSerializer的writeWithFormat
在com.alibaba.fastjson.serializer.JSONSerializer中

public final void writeWithFormat(Object object, String format) {
        if (object instanceof Date) {
            DateFormat dateFormat = this.getDateFormat();
            if (dateFormat == null) {
                dateFormat = new SimpleDateFormat(format, locale);
                dateFormat.setTimeZone(timeZone);
            }
            String text = dateFormat.format((Date) object);
            out.writeString(text);
            return;
        }

全局配置覆盖了传入的format,使@JSONField配置无效
请问本身就是这样设计的还是有bug