vue中使用swiper輪播第二遍無法點(diǎn)擊是為什么？

做了一個點(diǎn)擊放大圖片效果，但是當(dāng)輪播到第二遍的時候第一張圖就無法點(diǎn)擊了，是為什么？
順便問下swiper4怎么用懶加載圖，我設(shè)置lazyLoadin為true為什么沒效果？
現(xiàn)在懷疑是loop作怪，求大神

  <swiper :options="swiperOption" ref="mySwiper">
      <swiper-slide v-for="(img,index) in banner" :key="index">
          <img :src="img.src" alt="" @click="select(index)" 
    :class="{big: index===selectIndex}">
      </swiper-slide>
      <div class="swiper-pagination" slot="pagination"></div>
      <!-- <div class="swiper-button-prev" slot="button-prev"></div>
      <div class="swiper-button-next" slot="button-next"></div> -->
    </swiper>
    

data{
swiperOption: {

    loop: true,
       lazyLoading: {
         lazyLoading: true,
         lazyLoadingInPrevNext: true,
       },
    autoplay: {
      disableOnInteraction: false,
      stopOnLastSlide: true
    },
    // 如果需要分頁器
    pagination: {
      el: ".swiper-pagination",
      clickable: true
    }
  },
selectIndex: undefined,
},
methods: {
select (index) {
           this.selectIndex = this.selectIndex === index ? undefined : index;
           console.log(this.selectIndex === index);
       }
}