Problem with variations in the cart.

Hi.

I′m unsing woocommerce 3.0.7 and I set up some products with variations. The proplem is, that they are displayed in the cart in different ways. Even when its the same product and variation, they are displayed differently. Futhermore sometimes the variations are totally missing in the checkout.

Here are some screenshots for better understanding:

Cart: https://prnt.sc/f9bard
Checkout: https://prnt.sc/f9bazf

Here is a staging site with sample product:
https://staging3.metall-fachhandel.de/produkt/aluminium-rundstangen-alznmgcu15-7075/

Hope sombody has ideas or can help me with this struggle.
cheers, Tobi