diff --git a/src/activitypub/notes.js b/src/activitypub/notes.js
index 1c9ff7f285..c57ae3ed9a 100644
--- a/src/activitypub/notes.js
+++ b/src/activitypub/notes.js
@@ -91,7 +91,7 @@ Notes.assertTopic = async (uid, id) => {
 	 */
 
 	const chain = Array.from(await Notes.getParentChain(uid, id));
-	const { pid: tid, uid: authorId } = chain[chain.length - 1];
+	const { pid: tid, uid: authorId, timestamp } = chain[chain.length - 1];
 
 	const members = await db.isSortedSetMembers(`tidRemote:${tid}:posts`, chain.map(p => p.pid));
 	if (members.every(Boolean)) {
@@ -118,6 +118,7 @@ Notes.assertTopic = async (uid, id) => {
 			mainPid: tid,
 			title: 'TBD',
 			slug: `remote?resource=${encodeURIComponent(tid)}`,
+			timestamp,
 		}),
 		db.sortedSetAdd(`tidRemote:${tid}:posts`, timestamps, ids),
 		Notes.assert(uid, unprocessed),
@@ -125,6 +126,8 @@ Notes.assertTopic = async (uid, id) => {
 	await Promise.all([ // must be done after .assert()
 		Notes.assertParentChain(chain),
 		Notes.updateTopicCounts(tid),
+		topics.updateLastPostTimeFromLastPid(tid),
+		topics.updateTeaser(tid),
 	]);
 
 	return tid;
diff --git a/src/controllers/activitypub/topics.js b/src/controllers/activitypub/topics.js
index bc2152bb2a..aae87065e2 100644
--- a/src/controllers/activitypub/topics.js
+++ b/src/controllers/activitypub/topics.js
@@ -22,7 +22,7 @@ controller.get = async function (req, res, next) {
 
 	const tid = await notes.assertTopic(req.uid, req.query.resource);
 
-	let postIndex = await db.sortedSetRank(`tidRemote:${tid}:posts`, req.query.resource);
+	let postIndex = Math.max(1, await db.sortedSetRank(`tidRemote:${tid}:posts`, req.query.resource));
 	const [
 		userPrivileges,
 		settings,
diff --git a/src/topics/data.js b/src/topics/data.js
index 12bb949e8c..859de72395 100644
--- a/src/topics/data.js
+++ b/src/topics/data.js
@@ -64,11 +64,13 @@ module.exports = function (Topics) {
 	};
 
 	Topics.setTopicField = async function (tid, field, value) {
-		await db.setObjectField(`topic:${tid}`, field, value);
+		const setPrefix = activitypub.helpers.isUri(tid) ? 'topicRemote' : 'topic';
+		await db.setObjectField(`${setPrefix}:${tid}`, field, value);
 	};
 
 	Topics.setTopicFields = async function (tid, data) {
-		await db.setObject(`topic:${tid}`, data);
+		const setPrefix = activitypub.helpers.isUri(tid) ? 'topicRemote' : 'topic';
+		await db.setObject(`${setPrefix}:${tid}`, data);
 	};
 
 	Topics.deleteTopicField = async function (tid, field) {
diff --git a/src/topics/posts.js b/src/topics/posts.js
index 603bc465b9..6c9d53aee0 100644
--- a/src/topics/posts.js
+++ b/src/topics/posts.js
@@ -231,15 +231,16 @@ module.exports = function (Topics) {
 	Topics.getLatestUndeletedReply = async function (tid) {
 		let isDeleted = false;
 		let index = 0;
+		const setPrefix = activitypub.helpers.isUri(tid) ? 'tidRemote' : 'tid';
 		do {
 			/* eslint-disable no-await-in-loop */
-			const pids = await db.getSortedSetRevRange(`tid:${tid}:posts`, index, index);
+			const pids = await db.getSortedSetRevRange(`${setPrefix}:${tid}:posts`, index, index);
 			if (!pids.length) {
 				return null;
 			}
 			isDeleted = await posts.getPostField(pids[0], 'deleted');
 			if (!isDeleted) {
-				return parseInt(pids[0], 10);
+				return pids[0];
 			}
 			index += 1;
 		} while (isDeleted);