Error key warning in Scheduler version 4.14.1

I used editItem property to update view of item, but got issue as below. I am using scheduler version 4.14.1. Please tell me how to fix it. You can see sample code in this link :https://stackblitz.com/edit/react-pwcye5?file=app%2Fmain.tsx

Encountered two children with the same key, `undefined:0:0`. Keys should be unique so that components maintain their identity across updates. Non-unique keys may cause children to be duplicated and/or omitted — the behavior is unsupported and could change in a future version.
    at div
    at div
    at SchedulerViewContext (https://react-pwcye5.stackblitz.io/turbo_modules/@progress/kendo-react-scheduler@5.12.1/dist/npm/context/SchedulerViewContext.js:56:23)
    at eval (https://react-pwcye5.stackblitz.io/turbo_modules/@progress/kendo-react-scheduler@5.12.1/dist/npm/components/BaseView.js:15:25)
    at MultiDayView (https://react-pwcye5.stackblitz.io/turbo_modules/@progress/kendo-react-scheduler@5.12.1/dist/npm/views/day/MultiDayView.js:51:62)
    at KendoReactSchedulerDayView
    at divat SchedulerContext (https://react-pwcye5.stackblitz.io/turbo_modules/@progress/kendo-react-scheduler@5.12.1/dist/npm/context/SchedulerContext.js:189:23)
    at eval (https://react-pwcye5.stackblitz.io/turbo_modules/@progress/kendo-react-scheduler@5.12.1/dist/npm/Scheduler.js:62:26)