Modular page outputs plain html code instead of a rendered data

Hi there!
I’m facing strange problem.
I had a working website with modular overriden templates.
As a next step I decided to rebuild it with a Gantry 5 framework.
Well, the home page does work, but strange thing happen with other pages.

For instance, I have a Main services page. Page template is set to Modular.
And it have some of code:

title: Test
    items: '@self.modular'
        by: default
        dir: asc
body_classes: services
menu: Test
slug: test
    markdown: true
    twig: true
onpage_menu: false
background: test.jpg

{% set image = theme_url ~ '/images/' ~ page.header.background %}
<div class="static_header" style="background-image: url('{{ image }}'); background-position: 0% 40%" >                                           
	<div class="overlay"> 

This piece of code renders perfectly.

Next child modular page _intro:

title: Services
published: true
menu: MenuName
image_align: left

<section class="service-container container-fluid">
    <div class="row no-gutters">
	{% for image in %}
        <div class="col-sm-12 col-md-12 col-lg-6 col-xl-3 py-2">		
            <div class="card card-body h-100">
				<div class="service-feature-box">
					<div class="service-media">
						{{ image.cropResize(806,582).html }}						
				   <div class="service-body">
					 <div class="custom-heading centered">
					   <h4>{{ image.meta.heading[grav.language.getLanguage] }}</h4>            
					<p class="text-justify">{{ image.meta.description[grav.language.getLanguage] }}</p>                  
		{% endfor %}

and it features custom page template, called services.html.twig.
here is a code:

<section class="container-fluid">
   <div class="row no-gutters">
	   <div class="col-md-12"> 
		   <div id="content-slide">
		  <div class="slideme">
		 <div class="showcase-inner">
			  {{ content }}

As a result the modular child page outputs plain html. Do I’m missing something?

|raw have to be place on every output