fix: missing postAtIndex handling

src/controllers/topics.js

@@ -249,10 +249,6 @@ async function addTags(topicData, req, res) {
 			rel: 'canonical',
 			href: `${url}/topic/${topicData.slug}`,
 		},
-		{
-			rel: 'author',
-			href: `${url}/user/${postAtIndex.user.userslug}`,
-		},
 	];
 
 	if (!topicData['feeds:disableRSS']) {
@@ -269,6 +265,13 @@ async function addTags(topicData, req, res) {
 			href: `${url}/category/${topicData.category.slug}`,
 		});
 	}
+
+	if (postAtIndex) {
+		res.locals.linkTags.push({
+			rel: 'author',
+			href: `${url}/user/${postAtIndex.user.userslug}`,
+		});
+	}
 }
 
 async function addOGImageTags(res, topicData, postAtIndex) {