This error occurs when the inventory module is enabled, yet the inventory is not used. The issue can be resolved by adjusting the InventoryResolver.php file that is located either in the app/code/Amasty/Feed/Model/ or vendor/amasty/feed/Model/ directory.
Please open the file and find the following line: return $this->moduleManager->isEnabled(self::MAGENTO_INVENTORY_MODULE_NAMESPACE);
In that line, add "false; //" after return
Should you require any assistance with adjusting the file, please do contact our Support Team.