Why do items that are not available appear as in stock?

Start by verifying the stock formula within the CMS.

Additionally, it is possible that the problem is caused by the fact that there are multiple warehouses with different stock levels in Exact Online. If there are multiple warehouses, the CMS randomly retrieves stock information.

You have the option to focus on stock within a specific warehouse. To achieve this, fill the Warehouse used for stock setting with the corresponding warehouse code. The setting can be found via Administration > Settings > Connector settings tab.

Once the setting has been modified, start an item synchronization to update the stock.