Primary tag slug not working in certain context

I’m trying to show a list of posts with the tag “Popular” (which is not the first tag) and on this list I want it to show the primary tag of the post. If I use {{reading_time}} in the same context it works, but not with {{}}. Why am I unable to grab the primary tag for the post in this context? It works in other contexts.

<div class="col-2">
    {{#get "posts" filter="tags:popular+featured:false" limit="5" }}
        <h2 class="section-title" style="margin-left: 0;">Popular <a href="/blog/tag/updates/" class="section-all">SEE ALL</a>
        <div class="popular-posts-block">
            {{#foreach posts}}
                <div class="popular-post-line row" onClick="window.location.href = '{{url}}';">
                    <div class="col-3-mob popular-post-image">
                        <a href="{{url}}">
                            <img class="popular-post-image"
                                 srcset="{{img_url feature_image size="s"}} 300w,
                                            {{img_url feature_image size="m"}} 600w,
                                            {{img_url feature_image size="l"}} 1000w,
                                            {{img_url feature_image size="xl"}} 2000w"
                                 sizes="(max-width: 1000px) 400px, 700px"
                                 src="{{img_url feature_image size="m"}}"
                    <div class="post-card-content">
                        <a class="post-card-content-link popular-post-content-link" href="{{url}}">
                            <header class="post-card-header">
                                <p class="post-card-title popular-post-title">{{title}}</p>
                    <div class="popular-posts-tags col-3-mob">
                            <span class="popular-posts-tags"><b class="post-card-tag-name">{{}}</b>

If you want to fetch tags for the posts, as well as filter by tag, you’ll need to explicitly include them:

{{#get "posts" filter="tags:popular+featured:false" include="tags" limit="5" }}

More detail in the get helper docs: