As `_do_unreserve` was rewrited, the `_decrease_reserved_quanity` method isn't useful since its purpose was to avoid to unlink all stock moves and it is what `_do_unreserve` cares about. See 2e41338f42e2ef9f2ac2b3e73b274c4af242b28a closes odoo/odoo#42582 Related: odoo/enterprise#7488 Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>