Version

2.12.3

Environment

win10, chrome 57.0.2987.133,

Reproduction link

https://codepen.io/w567675/pen/QMGNoG?editors=001

Steps to reproduce

1. select date
2. click allowClear
3. select date

What is expected?

no errors

What is actually happening?

Uncaught TypeError: Cannot read property 'clone' of undefined
at Object.getEndValue (RangeCalendar.js:333)
at Object.render (RangeCalendar.js:518)
at react-dom.js:5257
at measureLifeCyclePerf (react-dom.js:4537)
at ReactCompositeComponentWrapper._renderValidatedComponentWithoutOwnerOrContext (react-dom.js:5256)
at ReactCompositeComponentWrapper._renderValidatedComponent (react-dom.js:5283)
at ReactCompositeComponentWrapper._updateRenderedComponent (react-dom.js:5207)
at ReactCompositeComponentWrapper._performComponentUpdate (react-dom.js:5185)
at ReactCompositeComponentWrapper.updateComponent (react-dom.js:5106)
at ReactCompositeComponentWrapper.receiveComponent (react-dom.js:5008)