title: the scroll bar does not respond when assigning a value to scollTop (mobile only)
body: <h3>Problem Description</h3>
  
  <p>xx.scrollTop = xx is used in web API IntersectionObserver. After testing, it is completely normal on pc, and the scroll bar scrolls. However, on the mobile terminal (Android), although the assignment is successful, there is no scrolling.</p>
  
  <h3>Environment</h3>
  
  <p>no frame used</p>
  
  <h3>Code</h3>
  
  <pre class="lang-js prettyprint-override"><code>    this.selectedItem = new IntersectionObserver((entries) =&gt; {
        entries.forEach((item) =&gt; {
          if (item.isIntersecting) {
          // -------------------------------------this line
            this.yearScrollEl.scrollTop = 100
          }
        })
      }, {
        root: this.element.querySelector('.timePicker-wheel'),
        threshold: [0.6]
      })
  
      this.element.querySelectorAll('li').forEach((item) =&gt; {
        this.selectedItem.observe(item)
      })
  </code></pre>
  
  <h3>Tried method</h3>
  
  <p>After adding a timer, the scroll bar is in effect:</p>
  
  <pre><code>setTimeout(() =&gt; {
      this.yearScrollEl.scrollTop = 100
  },300)
  </code></pre>
  
  <p>But I don’t know the principle, if anyone can tell me the answer I will be very grateful</p>