Hi devzest01
It seems there was an issue with the latest version that was not uploaded correctly to the WordPress.org repository.
Please, try to update to version 1.9.53 that we have just released, and it should fix all those issues.
If that version is still not available on your site, it can be downloaded from the plugin page:
https://wordpress.org/plugins/atum-stock-manager-for-woocommerce/
We are sorry for any inconvenience caused.
Best Regards,
Salva.