Index.htm and |page not working

Need Help
#1

In the template along the path pages/* there are different htm files and all have the url parameter at the top

In my case

index.htm url = "/"
page.htm url = "/:fullslug*"

The problem is that I use |link to generate links in the menu. When I go to the main page, index.htm works and all menu links think that they are active, that is, the parameter isActive = true

menu example

{% for item in menu.get() %}
    {% if item.header %}
        <li class="header-menu__item">
            {% set menu_url = link('october://entry-'~item.blueprint_uuid~'@link/'~item.id) %}
            <a href="{{ menu_url.url }}" {{ item.external ? 'target="_blank" ' }}
                class="header-menu__link">
                {{ item.title }}
            </a>
        </li>
    {% endif %}
{% endfor %}
#2

Maybe more code will clarify your problem. to be honest, I don’t understand exactly. from your code, isActive is nowhere to be seen…
in the code you refer to entries but you ask about .htm files
Are you using staticPages Menu or something custom?

#3

This is how I get the link. When I am on any other than the main page, the urls that are needed are returned, but when I get to the main page, all pages have the url address of the main page. I think the problem is in pages/index.htm

{% set menu_url = 'october://entry-'~item.blueprint_uuid~'@link/'~item.id %}
{{ menu_url|link }}

header.htm

[collection menu]
handle = "Content\Page"

{% for item in menu.get() %}
    {% if item.header %}
        <li class="header-menu__item">
            {% set menu_url = 'october://entry-'~item.blueprint_uuid~'@link/'~item.id %}
            <a href="{{ menu_url|link }}" {{ item.external ? 'target="_blank" ' }}
                class="header-menu__link">
                {{ menu_url }}
                {{ item.title }}
            </a>
        </li>
    {% endif %}
{% endfor %}
==

pages/index.htm

url = "/"
layout = "default"
title = "Page"

[global settings]
handle = "Content\Settings"
==

pages/page.htm

url = "/:fullslug*"
layout = "default"
title = "Page"

[section]
handle = "Content\Page"
entrySlug = "{{ :fullslug }}"
entryColumn = "fullslug"
entryDefault = 1

[global settings]
handle = "Content\Settings"
==
#4

Try changing to something like this

{% set menu_url = 'page'|page({ id: item.id, slug: item.slug, fullslug: item.fullslug }) %}