Error occurs after Grav admin upgrade to 1.1.8

Hi there, my page which contains media collection at the frontmatter. it works to v1.1.5. After upgrade, error appear just on this page "can't convert undefinded object". image is attached for reference. thank you

frontmatter :-
media:
images:

• /KAY_0037.JPG

• /KAY_0147.en.jpg.meta.yaml

  Untitled-1

Can you paste the whole page, and the page blueprint ? Use triple backticks to properly format code.

i copied the same files in 1.1.5 version and 1.1.8 version. And i tried to remove the media from frontmatter with no content. the images and the .yaml file are placed in the same folder as page (.md)

blueprint:-

title: Fido Playing with his Bone
description: The other day, Fido got a new bone, and he became really captivated by it.

content of the page is blank, just frontmatter:-

title: 'Photo Gallery'
menu: 'Photo Gallery'

template for the page (gallery.html.twig)

{% extends 'partials/base.html.twig'  %}

{% block content %}

    {{ page.header.title }}

     <div class="image-gallery">

    {% for image in page.media.images %}

    <div class="gallery-item">
        <div class="image-surround">
            {{ image.lightbox(1024,768).resize(200,200).html('Sample Image') }}
        </div>
        <div class="image-info">
            <p class="image-title">{{ image.meta.title }}</p>
            <p class="image-desc">{{ image.meta.description }}</p>
        </div>
    </div>
    {% endfor %}
    </div>

{% endblock %}

it works fine in version 1.1.5. In version 1.1.8 same error still appears.

Better create an issue for this: https://github.com/getgrav/grav/issues

Issue is created. https://github.com/getgrav/grav/issues/1166