This problem occurs mainly when user is using a little bit slower internet or mobile for example. But flashing is sometimes also seen on higher speeds when page content / images in carousel hasn't been cached.
If page loads and first elements are being rendered, all carousel "slides" are under each other like a list, then page gets loaded, magic happens and every extra slide disappears and carousel has been born.
Is this default Owl behaviour? How should I solve this? This is very ugly-looking and unprofessional.