Hello Philip,

This behavior is a known limitation of the Kendo UI Pager in responsive mode. When the Pager is initialized while its container is hidden (such as inside a tab panel or a collapsed section), it may not render correctly once it becomes visible. This happens because the Pager cannot accurately calculate its size or responsive layout when its parent container has no visible dimensions.

Workaround

To address this, you can manually refresh the Pager after making its container visible. This forces the Pager to recalculate its layout and render properly:

// After showing the container or tab
$("#pager").data("kendoPager").refresh();

The behavior is described also in the following article:

- https://www.telerik.com/kendo-jquery-ui/documentation/knowledge-base/hidden-widgets-displayed-incorrectly-raise-errors

I am changing the status of the current issue to 'Unplanned'. We will monitor the community interest and based on the votes the issue gathers it could be considered for implementation in a future release. 

Regards,
Neli
Progress Telerik