UndoManager undo action

[Oueio]

I'd implemented action in rte toolbar that acts as creating list from text component

editor.RichTextEditor.add('add-ulist', {
    icon: '&#8226',
    attributes: {title: 'Список'},
    async result(rte: any) {
        const cmp = rte.em.getSelected();
        editor.selectRemove(cmp);
        const el = cmp.getEl();
        const range = rte.selection().getRangeAt(0);
        const upperRange = new Range();
        upperRange.setStartBefore(el.childNodes[0]);
        upperRange.setEnd(range.startContainer, range.startOffset);
        const lowerRange = new Range();
        lowerRange.setEndAfter(el.childNodes[el.childNodes.length - 1]);
        lowerRange.setStart(range.endContainer, range.endOffset);

        function getHTML(someRange: any) {
            const contents = someRange.cloneContents();
            const div = document.createElement('div');
            div.append(...contents.childNodes);
            return div.innerHTML;
        }

        const upperHTML = getHTML(upperRange);
        const html = getHTML(range);
        const lowerHTML = getHTML(lowerRange);
        const cmpIndex = cmp.index();
        const cmpStyle = cmp.getStyle();
        const cmpParent = cmp.parent();
        if (upperHTML.length > 0) {
            const appended = cmpParent.append({
                type: 'main-text'
            }, {at: cmpIndex})[0];
            appended.setStyle(cmpStyle);
            appended.getEl().innerHTML = upperHTML.trim();
        }
        if (lowerHTML.length > 0) {
            const appended = cmpParent.append({
                type: 'main-text'
            }, {at: cmpIndex + 1})[0];
            appended.setStyle(cmpStyle);
            appended.getEl().innerHTML = lowerHTML.trim();
        }
        const list = cmpParent.append({
            type: 'ulist'
        }, {at: cmpIndex + 1})[0];
        const splitted = html.trim().split('\n');
        for (const line of splitted) {
            const li = list.append({
                type: 'list'
            })[0];
            const main = li.append({
                type: 'main-text'
            })[0];
            main.setStyle(cmpStyle);
            main.getEl().innerHTML = line.trim();
        }
        cmp.remove();
    }
});

Everything is okay. But when i try to undo this action, it almost working fine, expect text component after undoing have no text.
Do you have any suggestions how to fix it?
Video implementation

bug.mp4