CSS transition not a drop-in substitute for

[vidjuheffex]

Do you want to request a feature or report a bug?
Report a bug
What is the current behavior?
React app crashes:
CSSTransition.js:227 Uncaught TypeError: Cannot read property 'enter' of undefined at CSSTransition._this.getClassNames (CSSTransition.js:227)

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:
Had a transition component, replaced it with csstransition because I was getting a delay on the enter animation. From what I understand these should swap out easily.

      <CSSTransition
        in={inProp}
        timeout={parseInt(duration, 10)}
        appear={appear}
      >
        {state => {
          console.log(state)
          return (
            <Tag
              {...getAttributes()}
            >
              {renderChildren()}
            </Tag>
          );
        }}
      </CSSTransition>
    );

What is the expected behavior?
Same as when I used the transition component.

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?
16.2, chrome mac os x high sierra