Extjs Date field Rowediting Losing It's Value

I have a grid with RowEditing enabled with some dateFields and when I try to edit, date field value gets blanked. Forcing the user to select the date again. Though upon cancel edit, old values are displayed. attached screenshot dateFieldGetBlanked

{
    text: 'Quote Date',
    dataIndex: 'quote_date',
    menuDisabled: true,
    xtype: 'datecolumn',
    format:'M d, Y',
    flex: 1,
    editor: {
        xtype : 'datefield', 
        allowBlank : false
    }
}

This behavior is not replicable in cellediting, it works fine there.

Any idea whats causing this problem in rowediting, any solutions for this?

type: 'date' inside modal fields array should fix it.

Here is behaviour replicated. Fiddle with type:date : https://fiddle.sencha.com/#view/editor&fiddle/2nj0 Fiddle with datefield as string: https://fiddle.sencha.com/#view/editor&fiddle/2nj1