I also had the same problem, as a workaround I disabled track â€œinventory with optionsâ€ in that product and it went away, of course this doesnâ€™t truly solve the problem, hopefully CS-Cart is aware of this bug.
many clients for many years use inventory combinations for their inventory amounts. Since option combinations are deprecated a serious issue arose because there are many integrations with ERP software depending on this procedure.
If you wanted to give the new ability of variations you should leave inventory combinations too, so the client can select what is more suitable for him.
The solution is to online update from v.4.9.3, during the update a new add-on will be installed, called Product option combinations, with this add-on you can also use the old product options/variants from v.4.10.1.
I assume if someone requests this add-on from helpdesk, they will send it if the mentioned update is not possible.
Our Back in Stock add-on is also compatible with this add-on, you can have back in stock subscribers/notifications for options/variants from cs-cart v.4.10.1