先上BUG

解决方案

  /* 设置滚动条的样式 */
  /deep/::-webkit-scrollbar {
      width: 10px !important;
      height:10px !important;
      background-color: #8487879e;
  }

  /deep/ .el-table__fixed::before, .el-table__fixed-right::before {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 1px;
    background-color: unset;
    z-index: 4;
}

搞定