Thank you for your reply.
If I want Slick working I have to set 'Add slick.js' and 'Add this slick js' to [Yes] in template serrings.
I've checked again and I think I'm not loading slick twice.
However, there is an inline <script> in the <head> of my template that is crated by Sebld I guess.
In this, some Slick parameters are called twice.
jQuery(document).ready(function(){jQuery('.partners-carousel').slick({
prevArrow: '<button data-role="none" aria-label="Previous" tabindex="0" role="button">Previous</button>',
nextArrow: '<button data-role="none" aria-label="Next" tabindex="0" role="button">Next</button>',
centerPadding: '50px',
focusOnSelect: true,
mobileFirst: true,
slidesPerRow: 5,
slidesToShow: 5,
swipeToSlide: true,
});
});