Standard and custom Slider Arrows act different (skipping slides)

Hi there Webflow Community,

I am currently struggling with custom positioning of my slider arrow navigation. I followed this tutorial to achieve a custom position for my slider arrows:

Everything worked out in the beginning, but somewhere along working on my site, the custom slider arrows suddenly are skipping every second slide. The problem is: The standard slider arrows do work fine without skipping any slides.

I isolated the problematic section and linked my Read-Only site below, I am at the end of my rope (at the moment) and cannot seem to find the error or oversight that caused this slider behaviour.

The big blue arrows are the standard webflow slider arrows. The arrows positioned below the headline (left column) are the custom positioned arrows from the tutorial I linked above.

What I tested as well: When just copying the “neuigkeiten” section into a whole new webflow project, both slider arrow groups work fine (custom and standard). But adding any other content reverts the custom arrows to skipping slides. Maybe I missed a styling somewhere… I hope someone can point me into the right direction.

Heres the actual content with custom code:

Below you will find the webflow designer preview.

Here is my site Read-Only: Webflow - Card Slider
(Webflow - Card Slider)