diff --git a/_includes/components/post-navigation.njk b/_includes/components/post-navigation.njk
index 42d35eb..8de0dbe 100644
--- a/_includes/components/post-navigation.njk
+++ b/_includes/components/post-navigation.njk
@@ -12,10 +12,11 @@
       {% set _bookmarkedUrl = _prevPost.data.bookmarkOf or _prevPost.data.bookmark_of %}
       {% set _repostedUrl = _prevPost.data.repostOf or _prevPost.data.repost_of %}
       {% set _replyToUrl = _prevPost.data.inReplyTo or _prevPost.data.in_reply_to %}
-      {% set _prevHasOg = _prevPost.fileSlug | hasOgImage %}
+      {% set _prevOgSlug = _prevPost.url | ogSlug %}
+      {% set _prevHasOg = _prevOgSlug | hasOgImage %}
       <a href="{{ _prevPost.url }}" class="group flex items-start gap-3 text-sm text-primary-600 dark:text-primary-400 hover:underline">
         {% if _prevHasOg %}
-        <img src="/og/{{ _prevPost.fileSlug }}.png" alt="" class="w-20 h-[42px] object-cover rounded flex-shrink-0 opacity-80 group-hover:opacity-100 transition-opacity" loading="lazy" eleventy:ignore>
+        <img src="/og/{{ _prevOgSlug }}.png" alt="" class="w-20 h-[42px] object-cover rounded flex-shrink-0 opacity-80 group-hover:opacity-100 transition-opacity" loading="lazy" eleventy:ignore>
         {% endif %}
         <span class="line-clamp-2 flex items-center gap-1.5">
           {% if _likedUrl %}
@@ -46,7 +47,8 @@
       {% set _bookmarkedUrl = _nextPost.data.bookmarkOf or _nextPost.data.bookmark_of %}
       {% set _repostedUrl = _nextPost.data.repostOf or _nextPost.data.repost_of %}
       {% set _replyToUrl = _nextPost.data.inReplyTo or _nextPost.data.in_reply_to %}
-      {% set _nextHasOg = _nextPost.fileSlug | hasOgImage %}
+      {% set _nextOgSlug = _nextPost.url | ogSlug %}
+      {% set _nextHasOg = _nextOgSlug | hasOgImage %}
       <a href="{{ _nextPost.url }}" class="group flex items-start gap-3 text-sm text-primary-600 dark:text-primary-400 hover:underline {% if _prevPost %}justify-end{% endif %}">
         <span class="line-clamp-2 flex items-center gap-1.5 {% if _prevPost %}justify-end{% endif %}">
           {% if _likedUrl %}
@@ -66,7 +68,7 @@
           {% endif %}
         </span>
         {% if _nextHasOg %}
-        <img src="/og/{{ _nextPost.fileSlug }}.png" alt="" class="w-20 h-[42px] object-cover rounded flex-shrink-0 opacity-80 group-hover:opacity-100 transition-opacity" loading="lazy" eleventy:ignore>
+        <img src="/og/{{ _nextOgSlug }}.png" alt="" class="w-20 h-[42px] object-cover rounded flex-shrink-0 opacity-80 group-hover:opacity-100 transition-opacity" loading="lazy" eleventy:ignore>
         {% endif %}
       </a>
     </div>
diff --git a/_includes/layouts/base.njk b/_includes/layouts/base.njk
index 70ac985..e6d009c 100644
--- a/_includes/layouts/base.njk
+++ b/_includes/layouts/base.njk
@@ -23,7 +23,8 @@
   <meta property="og:type" content="{% if page.url == '/' %}website{% else %}article{% endif %}">
   <meta property="og:description" content="{{ ogDesc }}">
   <meta name="description" content="{{ ogDesc }}">
-  {% set hasGeneratedOg = page.fileSlug | hasOgImage %}
+  {% set ogFileSlug = page.url | ogSlug %}
+  {% set hasGeneratedOg = ogFileSlug | hasOgImage %}
   {% if ogPhoto and ogPhoto != "" and (ogPhoto | length) > 10 %}
   <meta property="og:image" content="{% if 'http' in ogPhoto %}{{ ogPhoto }}{% else %}{{ site.url }}{% if ogPhoto[0] != '/' %}/{% endif %}{{ ogPhoto }}{% endif %}">
   {% elif image and image != "" and (image | length) > 10 %}
@@ -31,7 +32,7 @@
   {% elif contentImage and contentImage != "" and (contentImage | length) > 10 %}
   <meta property="og:image" content="{% if 'http' in contentImage %}{{ contentImage }}{% else %}{{ site.url }}{% if contentImage[0] != '/' %}/{% endif %}{{ contentImage }}{% endif %}">
   {% elif hasGeneratedOg %}
-  <meta property="og:image" content="{{ site.url }}/og/{{ page.fileSlug }}.png">
+  <meta property="og:image" content="{{ site.url }}/og/{{ ogFileSlug }}.png">
   {% else %}
   <meta property="og:image" content="{{ site.url }}/images/og-default.png">
   {% endif %}
@@ -51,7 +52,7 @@
   {% elif contentImage and contentImage != "" and (contentImage | length) > 10 %}
   <meta name="twitter:image" content="{% if 'http' in contentImage %}{{ contentImage }}{% else %}{{ site.url }}/{{ contentImage }}{% endif %}">
   {% elif hasGeneratedOg %}
-  <meta name="twitter:image" content="{{ site.url }}/og/{{ page.fileSlug }}.png">
+  <meta name="twitter:image" content="{{ site.url }}/og/{{ ogFileSlug }}.png">
   {% endif %}
 
   {# Favicon #}
diff --git a/eleventy.config.js b/eleventy.config.js
index 223a01e..5d8c3af 100644
--- a/eleventy.config.js
+++ b/eleventy.config.js
@@ -362,10 +362,18 @@ export default function (eleventyConfig) {
     }
   });
 
-  // Check if a generated OG image exists for this page slug
-  eleventyConfig.addFilter("hasOgImage", (fileSlug) => {
-    if (!fileSlug) return false;
-    const ogPath = resolve(__dirname, ".cache", "og", `${fileSlug}.png`);
+  // Derive OG slug from page.url (reliable) instead of page.fileSlug
+  // (which suffers from Nunjucks race conditions in Eleventy 3.x parallel rendering)
+  eleventyConfig.addFilter("ogSlug", (url) => {
+    if (!url) return "";
+    const last = url.replace(/\/$/, "").split("/").pop();
+    return last.replace(/^\d{4}-\d{2}-\d{2}-/, "");
+  });
+
+  // Check if a generated OG image exists for this slug
+  eleventyConfig.addFilter("hasOgImage", (slug) => {
+    if (!slug) return false;
+    const ogPath = resolve(__dirname, ".cache", "og", `${slug}.png`);
     return existsSync(ogPath);
   });