Thumbs slide class overriding not working

[AlexanderMatveev]

Describe the bug

Class not overriding

Reproduction

new Carousel(el, {
        Dots: false,
        Thumbs: {
            type: "classic",
            classes: {
                track: "f-thumbs__track", // this override works
                slide: "f-thumbs__slide myclass", // this override ignored
            }
        },
    },
    {Thumbs}
);

Additional context

No response