To reproduce:
-set AutoSizeMode to Fill
- Add view definition with two rows
- Add check box column to the view
-Set check box column minWidth 

Workaround:
Create a custom view definition, then create a custom ColumnGroupRowLayout class and override the GetClumnWidth method like this:
class MyViewDefinition : ColumnGroupsViewDefinition
{
 
    public MyViewDefinition()
    {
             
    }
    public override IGridRowLayout CreateRowLayout()
    {
        return new MyRowLayout(this);
    }
}
 
public class MyRowLayout : ColumnGroupRowLayout
{
 
    public MyRowLayout(ColumnGroupsViewDefinition view):base(view)
    {
 
    }
 
    public override int GetColumnWidth(GridViewColumn column)
    {
        return Math.Max( base.GetColumnWidth(column), column.MinWidth);
    }
}