Hi @zodiac1710,
It sounds like you might be experiencing the same issue described on this forum thread.
As explained there, this can happened if needed database tables aren’t correctly set up during a WooCommerce update. Products saved before the lookup table is fully set up may have incorrect data saved in there.
There’s a fix for the root cause of this problem included in WooCommerce 3.6.3 and newer. So, people who are only now updating won’t experience the problem.
However, if some incorrect data is already in place, it will need to be fixed on your site. To do this, please go to WooCommerce > Status > Tools and regenerate product lookup tables on that page:

Source: https://cld.wthms.co/09WNUg
It may take several minutes for the process to complete, depending on how many products there are in your store. Once it’s over, saving the product again will set the correct stock status. If there’s more than one product affected, you can either try bulk editing them, or updating the products via a CSV export/import.
Hopefully this helps!