Why does the browser refresh the page when navigating to another page?

Question

React

Why does the browser refresh the page when navigating to another page?

import Link from 'next/link';
<nav className="navigation">
                        <Link href="/proekty">
                            <a onClick={this.onToggleMenu} className="link">
                                Проекты
                            </a>
                        </Link>
                        <Link href="/agenstvo">
                            <a onClick={this.onToggleMenu} className="link">
                                Агентство
                            </a>
                        </Link>
                        <Link href="/kontakty">
                            <a onClick={this.onToggleMenu} className="link">
                                Контакты
                            </a>
                        </Link>
                        <Link href="/blog">
                            <a onClick={this.onToggleMenu} className="link">
                                Блог
                            </a>
                        </Link>
                    </nav>

import Router from 'next/router';
handlerScroll = () => {
        Router.push(`${this.props.path}`);
    };

When I go through the pages from the menu in the header, the page reloads, and if I do it while scrolling Router.push, it doesn’t reload, why?