[Waiting for user feedback] Woocommerce membership Purchasing Discount will add one product 16 times (4 x 4 languages)

Background of the issue:
I try to add Purchasing Discounts for a Membership. If WPML is not active, everything is fine and it keeps the Product or Product Category. If I have WPML active, it keeps one product 16 times. As we have 4 languages, it adds the product in each language and at least 4 times. So one product is 16 times in the list instead of 1. It's even possible to add Product Categories, but the categories are deleted. Link to a page where the issue can be seen: hidden link

I was in contatct with Membersup Support and got this answer, which is not acceptable:

Zach replied
Hey there Frank,

Thank you for getting back to me on this with these details and the login credentials!

I do not think we will need the login credentials from our side at this time, but if needed, I do greatly appreciate the access. Since you have determined that the error only occurs with all the WPML plugins active, it sounds as though you have confirmed the root issue. Like I noted earlier, there is incompatibilities with the way WPML handles creating duplicate posts and categories for each language in use and it causes a wide range of issues when attempting to set up memberships.

If you want to utilize WPML, you may try reaching out to their support for additional assistance on this issue. That said, to avoid issues with the Memberships with WPML, it would be recommended to create a membership plan and product for each language and utilize unique posts for each language to avoid these types of conflicts occurring.

I am sorry that I do not have better news for you on this, but I hope you have found the information helpful nonetheless!

Best wishes,
Zach

Symptoms:
Each product appears 16 times when WPML is active. Product categories are deleted.

Questions:
Why does each product appear 16 times when WPML is active?
How can I add product categories without them being deleted?