Woocommerce - Product add on - Not show meta info in frontend

I'm finishing a Woocommerce project and found the following situation;

My product has two variations;

I had to include a textarea on the product page for the customer to customize a message. This textarea was included using the plugin "product add-on"

When the plugin is active, changes and custom message, do not appear in email new application and will not appear on the order preview page.

When I disable the "product add on" the information of the variations are displayed normally in both email new application and also on the order preview page.

Can someone help me? because when the product add on is active, the information is not displayed correctly?

via Chebli Mohamed