Optionsflyout throws on bool? or DateOnly? if value=null

[VisualAlf]

if one or more of the values in a TableViewCheckboxColumn or in TableViewDateColumn is null, the TableViewColumnHeader.PrepareFilterItems(string? _filtertext) throws:
System.InvalidOperationException: 'Failed to compare two elements in the array.'

A Date value of null is handsome, when I want to display '' instead of Date...MinValue.