the effect is not as expected.

[liuhongjian0316]

---first--- 
<TransitionGroup style={{ height: '100%' }}>
            <CSSTransition
              key={location.key}
              classNames="fade"
              timeout={500}
              style={{ height: '100%' }}
              unmountOnExit
            >
              <Routes>
                <Route path="/new-chat" element={
                  AINewChat()
                } />
                <Route path="/chat" element={
                  <div>默认的聊天页面</div>
                } />
                <Route path="/" element={
                  <div>默认的聊天页面</div>
                } />
              </Routes>
            </CSSTransition>
          </TransitionGroup>

---second---
<TransitionGroup style={{ height: '100%' }}>
            <CSSTransition
              key={location.key}
              classNames="fade"
              timeout={500}
              style={{ height: '100%' }}
              nodeRef={nodeRef}
              unmountOnExit
            >
              <div ref={nodeRef}>
                <Routes>
                  <Route path="/new-chat" element={
![bug](https://github.com/reactjs/react-transition-group/assets/45460278/0e90d3b0-021f-4c5c-97b5-309c2bee2d55)

                    AINewChat()
                  } />
                  <Route path="/chat" element={
                    <div>默认的聊天页面</div>
                  } />
                  <Route path="/" element={
                    <div>默认的聊天页面</div>
                  } />
                </Routes>
              </div>
            </CSSTransition>
          </TransitionGroup>

 .fade-enter {
  opacity: 0;
  transform: scale(0.9);
}

.fade-enter-active {
  opacity: 1;
  transform: scale(1);
  transition: opacity 500ms, transform 500ms;
}

.fade-exit {
  opacity: 1;
  transform: scale(1);
}

.fade-exit-active {
  opacity: 0;
  transform: scale(0.9);
  transition: opacity 500ms, transform 500ms;
}

excessive effect is inconsistent,
'first' although there is a 'findDOMNode is deprecated and will be removed in the next major release. Instead' warning, the effect is as expected.
'second' the effect of displaying the page twice