Grids honor the [DisplayFormat(DataFormatString ... )] annotation for column content, but the FilterMenuType.CheckBoxList filter menu and the TelerikCheckBoxListFilter component don't. This is particularly noteworthy for formatting that truncates the contents such as DateTime which frequently tracks data smaller than user's care about, which can generate many visually identical checkboxes. To go along with the requested change, it would be nice if the filter matched off of the DisplayFormat string considering that is what the user sees and would therefore be referencing, since again, many DataFormatStrings can truncate data.

Because the TelerikCheckBoxListFilter component requires the field to match the data type of the grid's field, there isn't a way for the programmer to choose to show the filter menu with a checklist that matches the displayed values without building a fully custom FilterMenuTemplate with their own foreach loop and then figuring out a way to construct a CompositeFilterDescriptor filled with bracketing FilterDescriptors to account for the range of matching values. This is doubly troublesome since using the structure of CompositeFilterDescriptors needed to do that is not supported in the FilterMenuTemplate without also having to override the FilterMenuButtonsTemplate.

Generally speaking, it would make more sense to the users if the default options in the filter logically and visually matched with the default displayed values.

Reference material:
Grid column contents: https://www.telerik.com/blazor-ui/documentation/components/grid/columns/display-format
Checkbox List: https://www.telerik.com/blazor-ui/documentation/components/grid/filter/checkboxlist
Alternate FilterDescriptor shapes not supported: https://feedback.telerik.com/blazor/1681745-clear-button-in-grid-filtermenu-not-properly-clearing-custom-filter

Example Repl: https://blazorrepl.telerik.com/mJOSuxQw117zM1h321