title: collapse card opens then immediately closes again
body: <p>I've read previous threads that cover this issue for navbars and menus but it does not seem to apply.  I have a very simple example: two cards, one opened by default the other collapsed.  When I try to expand the second card by pressing Card 2 Button, it opens but then immediately closes again.  I am not sure what I'm doing wrong.</p>
  <p>Example here:</p>
  <pre><code>&lt;div id=&quot;accordion&quot;&gt;
      &lt;div class=&quot;card&quot;&gt;
          &lt;div class=&quot;card-header&quot; id=&quot;header1&quot;&gt;
              &lt;h5 class=&quot;mb-0&quot;&gt;
                  &lt;button class=&quot;btn btn-link&quot; data-toggle=&quot;collapse&quot; data-target=&quot;#collapse1&quot; aria-expanded=&quot;true&quot; aria-controls=&quot;collapse1&quot;&gt;
                      Card 1 Button
                  &lt;/button&gt;
              &lt;/h5&gt;
          &lt;/div&gt;
          &lt;div id=&quot;collapse1&quot; class=&quot;collapse show&quot; aria-labelledby=&quot;header1&quot; data-parent=&quot;#accordion&quot;&gt;
              &lt;div class=&quot;card-body&quot;&gt;
                  Card 1 Content
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
      &lt;div class=&quot;card&quot;&gt;
          &lt;div class=&quot;card-header&quot; id=&quot;header2&quot;&gt;
              &lt;h5 class=&quot;mb-0&quot;&gt;
                  &lt;button class=&quot;btn btn-link collapsed&quot; data-toggle=&quot;collapse&quot; data-target=&quot;#collapse2&quot; aria-expanded=&quot;false&quot; aria-controls=&quot;collapse2&quot;&gt;
                      Card 2 Button
                  &lt;/button&gt;
              &lt;/h5&gt;
          &lt;/div&gt;
          &lt;div id=&quot;collapse2&quot; class=&quot;collapse&quot; aria-labelledby=&quot;header2&quot; data-parent=&quot;#accordion&quot;&gt;
              &lt;div class=&quot;card-body&quot;&gt;
                  Card 2 Content
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>