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The reported issue will occur only after re-rendering the Scheduler without properly destroying the previous one. If you are re-rendering the Scheduler at any case kindly destroy the old one as shown below.
if (!ej.isNullOrUndefined($("#Schedule1").ejSchedule("instance"))) //here we are checking if old Schedule elements are present
$("#Schedule1").ejSchedule('destroy'); // here destroying the old one
If the above solution doesn’t fix the issue, kindly share the code example/sample (if possible)/image/video demo which clearly depicts your issue to serve you better.