The issue is that the time_window_close attribute is not being cast to a DateTime object by Laravel. To fix this, you can add the attribute to the $dates property in your Stop model:
class Stop extends Model
{
protected $dates = [
'time_window_close',
// add any other date attributes here
];
}
This will tell Laravel to cast the time_window_close attribute to a DateTime object, which should preserve the time component.