Hi,

Update the code like this,

def _get_min_qty(self):
    for prod_tml in self:
        product = self.env['product.product'].search([('product_tmpl_id', '=', prod_tml.id)])
        for pro in product:
            product_reorder = self.env['stock.warehouse.orderpoint'].search([('product_id', '=', pro.id)], limit=1)
            if product_reorder:
                prod_tml.min_qty = product_reorder.product_min_qty

or

def _get_min_qty(self):
    for prod_tml in self:
        product = self.env['product.product'].search([('product_tmpl_id', '=', prod_tml.id)], limit=1)
        product_reorder = self.env['stock.warehouse.orderpoint'].search([('product_id', '=', product.id)], limit=1)
        if product_reorder:
            prod_tml.min_qty = product_reorder.product_min_qty

Thanks