If a column configuration filter is applied to a lookup field, the loaded values could not be filtered or grouped in the grid.

This bug has been fixed: Lookup fields with column configuration filters now support correct grouping and filtering in the grid. Previously, filtered elements were grouped under an empty header and did not appear in the column filter options. Elements should now be grouped correctly, and all elements loaded in the grid should be available in the header filter.

Screenshot below highlights the incorrect behaviour prior to this fix: