Why does Slick Slider calculate slide height incorrectly?

Question

JavaScript

Good afternoon.
When first loaded on a phone (and only on a phone), Slick Slider calculates the height of the slides incorrectly:





When scrolling through several slides, everything becomes as it should. When you reload the slider is also normally loaded immediately. This is a dual slider, i.e. the bottom controls the top. All pictures are the same size. The bottom slider always works fine, although the pictures in it are the same. The empty area below the picture refers to the slide, because for it you can swipe the slider.

What could be the problem?

Answer 1

Decided:

rThisSlider.slick({
//параметры
}).on('setPosition', function (event, slick) {
  slick.$slides.css('height', slick.$slideTrack.find("img").height() + 'px');
});

Those. I equate the height of the slide to the height of the picture, and not to the height of the slider track.
But why this happens is unclear. Perhaps this is due to the image optimization module that is installed on the site.