i had a similar problem, Odoo send me this fix:
ARM created a fix for this. In order to implement it you need to follow these steps:
1.debug mode
2.technical/server actions
3.create
4.action name: e.g. fix unreserved qty
5.model: ir.actions.server
6.action to do: "execute python code"
7.copy/paste the fix underneath the pre-existing code
8."save"
9."create contextual action"
10.refresh page
11.action/fix "fix unreserved qty"
12.wait for it to load
13."remove contextual action"
14.action/delete