The standard configuration of Fastbay (with business policies support disabled in the module) involves the module sending payment, shipping, and return methods for each product based on the configured settings.
Under this condition, eBay will automatically create many new rules to group products if necessary. This is not an error; however, the eBay rules created will not be of any use as the module will send product data bypassing the eBay rules.
Furthermore, if you already have products on eBay with previously created and associated rules, these will be overwritten by the new rules unless you configure the product update type to “sync quantity or quantity/price.”
If you need to maintain the use of existing eBay business policies, the module offers the option to link existing eBay rules by associating them with eBay categories mapped in the module. Refer to the appropriate section (Business Policies) for more information.