`absolute_url` fails silently when `permalink` is defined

## Describe the bug

When `post.id` is undefined, the `post.url` filtered through `absolute_url` should be used. Branching via `if`/`else` functions as intended, however, for unknown reasons the `absolute_url` Jekyll filter is failing to produce a full URL. Instead only the collection name and post slug survives.

This seems to be some kind of bug that is triggered when `permalink` is defined/configured.

______

## Example Setup

`_config.yml` (snip)

```yaml
url: 'https://liquid-utilities.github.io'

collections_dir: documentation
collections:
example-collection:
output: true
permalink: /:collection/:name/
```

---

`_layout/test-absolute-url.html`

```liquid
{% assign collection__data = collection[page.collection_name] %}
{% for post in collection__data %}
URL: {{ post.url | absolute_url }}
{% endfor %}
```

---

`documentation/_exapmple-collection/test-absolute-url.md`

```markdown
---
layout: post
title: Tests Absolute URL Filter
description: Example post that collection layout will fail to parse URL for
---
```

---

`example-collection.html`

```html
---
layout: test-absolute-url
collection_name: example-collection
---
```

______

## Example Results

Build then navigate to example-collection URL similar to; `https://.github.io//example-collection.html`

Output will likely be presented similar to...

```text
URL: /example-collection/test-absolute-url
```

______

## Expected Behavior

Output _should_ be presented similar to...

```text
URL: https://.github.io//example-collection/test-absolute-url
```

... this is what `feed-atom` and `feed-rss2` layouts from `liquid-utilities` achieve, and there doesn't appear to be any major differences in how `post.url` is filtered by `absolute_url`

Start by reproducing the build with `_config.yml`, `_layout/test-absolute-url.html`, and the example collection files shown in the report. Compare the generated `post.url | absolute_url` output with the expected full URL, then verify the fix against the collection permalink setup and the feed layouts mentioned.

Written by the indexing model from the issue text.