Why is my angular kendo- timepicker not displayiing buttons until i hit refresh on the page?

Question

I am using a kendo-timepicker control that's mentioned here as below

<kendo-timepicker [(ngModel)] = "entity.time" name="scheduledTime" #scheduledTimeVar = "ngModel">
</kendo-timepicker>

Now when the page renders, sometimes the 'cancel' and 'set' buttons are missing. When I inspect the page.. shows me the html where the 'cancel' and 'set' button is like this:

<div class="k-time-footer k-action-buttons">
<button class="k-button k-time-cancel ng-star-inserted" ng-reflect-events="[object Object]" ng-reflect-scope="[object Object]" title="Cancel changes" aria-label="Cancel changes">Cancel</button>
<button class="k-time-accept k-button k-primary" ng-reflect-events="[object Object]" ng-reflect-scope="[object Object]" title="Set time" aria-label="Set time">Set</button>
</div> 

The cancel and set buttons sometimes just do not appear. Then when if I refresh the page. (F5), it does. Any idea why..? any help will be appreciated!