Impacted versions:
11.0

I don't know if it is an issue, but I think is strange.

`product_qty` is in unit of `product` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L240
`reserved_availability` is in unit of `stock.move` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L295

`move.product_qty - move.reserved_availability` seems to have no sens, no ?

https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L915
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L917
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L924

thank for your answer

@jco-odoo 
@alnslang 


addons/stock/models/stock_move.py
defaults = self.with_context(force_split_uom_id=self.product_id.uom_id.id)._prepare_move_split_vals(qty)
        if restrict_partner_id:
            defaults['restrict_partner_id'] = restrict_partner_id
        # 
        if self.env.context.get('source_location_id'):
            defaults['location_id'] = self.env.context['source_location_id']
        new_move = self.with_context(rounding_method='HALF-UP').copy(defaults)
        
        # 
        # 
        # 
        new_product_qty = self.product_id.uom_id._compute_quantity(self.product_qty - qty, self.product_uom, round=False)
        new_product_qty = float_round(new_product_qty, precision_digits=self.env['decimal.precision'].precision_get('Product Unit of Measure'))
        self.with_context(do_not_propagate=True, do_not_unreserve=True, rounding_method='HALF-UP').write({'product_uom_qty': new_product_qty})
        new_move = new_move._action_confirm(merge=False)
        return new_move.id
    def _recompute_state(self):
        for move in self:
            if move.reserved_availability == move.product_uom_qty:
                move.state = 'assigned'
            elif move.reserved_availability and move.reserved_availability <= move.product_uom_qty:
                move.state = 'partially_available'
            else:
                if move.procure_method == 'make_to_order' and not move.move_orig_ids:
                    move.state = 'waiting'
                elif move.move_orig_ids and not all(orig.state in ('done', 'cancel') for orig in move.move_orig_ids):
                    move.state = 'waiting'
                else:
                    move.state = 'confirmed'