Multi-Inventory breaking PO

I added a secondary inventory to a product and attempted to add it to a PO, resulting in an error, and inability to edit the PO line item any further. I cannot remove it, nor edit it. When adding the second inventory to the product, I also had to clone the existing inventory, as clicking on Add Inventory didn’t work.

I have included the on screen error and email error summary I received from my site below.

The error on the PO screen was as follows, with my site name edited out.
*******
`Fatal error: Uncaught ArgumentCountError: Too few arguments to function Atum\Inc\Helpers::get_atum_order_model(), 1 passed in /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-management-popup.php on line 32 and at least 2 expected in /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php:1708 Stack trace: #0 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-management-popup.php(32): Atum\Inc\Helpers::get_atum_order_model(2664) #1 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-panel.php(47): require(‘/home/customer/…’) #2 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php(1133): include(‘/home/customer/…’) #3 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory in /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php on line 1708
There has been a critical error on this website. Please check your site admin email inbox for instructions.
*******

The following was the email I received from my site, with my site name edited out.
******
When seeking help with this issue, you may be asked for some of the following information:
WordPress version 5.6.2
Current theme: Storefront (version 3.5.0)
Current plugin: ATUM Inventory Management for WooCommerce (version 1.8.6)
PHP version 7.4.15

Error Details
=============
An error of type E_ERROR was caused in line 1708 of the file /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php. Error message: Uncaught ArgumentCountError: Too few arguments to function Atum\Inc\Helpers::get_atum_order_model(), 1 passed in /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-management-popup.php on line 32 and at least 2 expected in /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php:1708
Stack trace:
#0 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-management-popup.php(32): Atum\Inc\Helpers::get_atum_order_model(2664)
#1 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory/views/meta-boxes/order-items/mi-panel.php(47): require(‘/home/customer/…’)
#2 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-stock-manager-for-woocommerce/classes/Inc/Helpers.php(1133): include(‘/home/customer/…’)
#3 /home/customer/www/**MYSITE**.COM/public_html/wp-content/plugins/atum-multi-inventory
*******