TypeError: Cannot read property '_currentElement' of null

[knowuh]

View details in Rollbar: https://rollbar.com/knowuh/Sage/items/243/

TypeError: Cannot read property '_currentElement' of null
  File "http://ivy.concord.org/js/globals.js", line 51714, in Object.ReactReconciler.unmountComponent
  File "http://ivy.concord.org/js/globals.js", line 43996, in ReactCompositeComponentMixin.unmountComponent
  File "http://ivy.concord.org/js/globals.js", line 51715, in Object.ReactReconciler.unmountComponent
  File "http://ivy.concord.org/js/globals.js", line 42331, in Object.ReactChildReconciler.updateChildren
  File "http://ivy.concord.org/js/globals.js", line 50516, in ReactDOMComponent.ReactMultiChild.Mixin._updateChildren
  File "http://ivy.concord.org/js/globals.js", line 50490, in ReactDOMComponent.ReactMultiChild.Mixin.updateChildren
  File "http://ivy.concord.org/js/globals.js", line 45455, in ReactDOMComponent.Mixin._updateDOMChildren
  File "http://ivy.concord.org/js/globals.js", line 45304, in ReactDOMComponent.Mixin.updateComponent
  File "http://ivy.concord.org/js/globals.js", line 45288, in ReactDOMComponent.Mixin.receiveComponent
  File "http://ivy.concord.org/js/globals.js", line 51756, in Object.ReactReconciler.receiveComponent