elment Table多级表头固定列后，合计行错位显示问题解决

<el-table-column :label="tabsDataFilters1.orgName" width="370" :fixed="tableFixed">
  <el-table-column type="index" label="序号" width="50" align="center" :fixed="tableFixed"></el-table-column>
  <el-table-column prop="name" label="姓名" width="200" align="left" :fixed="tableFixed"></el-table-column>
  <el-table-column prop="age" :formatter="formatAmount" label="小计" width="120" align="center" :fixed="tableFixed"></el-table-column>
</el-table-column>

mounted进行监听,监听方法如下：

observeClassChanges() {
  debugger
  this.$nextTick(() => {
    const bodyWrapper = this.$refs.table1.$el.querySelector('.el-table__body-wrapper');
    if (!bodyWrapper) return;

    // 创建 MutationObserver 监听 class 变化
    this.observer = new MutationObserver((mutationsList) => {
      for (const mutation of mutationsList) {
        if (mutation.attributeName === 'class') {
          this.removeScrollingClasses(bodyWrapper);
        }
      }
    });

    // 监听 `class` 变化
    this.observer.observe(bodyWrapper, {
      attributes: true,
      attributeFilter: ['class'],
    });

    // 初始移除 class，防止渲染时已有
    this.removeScrollingClasses(bodyWrapper);
  });
},
// 滚动中间行样式移除
removeScrollingClasses(bodyWrapper) {
  if (bodyWrapper.classList.contains('is-scrolling-middle')) {
    bodyWrapper.classList.remove('is-scrolling-middle');
  }
  if (bodyWrapper.classList.contains('is-scrolling-left')) {
    bodyWrapper.classList.remove('is-scrolling-left');
  }
},