diff --git a/src/activitypub/notes.js b/src/activitypub/notes.js
index f3608e5c4f..d808f3abac 100644
--- a/src/activitypub/notes.js
+++ b/src/activitypub/notes.js
@@ -76,7 +76,7 @@ Notes.assert = async (uid, input, options = { skipChecks: false }) => {
 	mainPid = utils.isNumber(mainPid) ? parseInt(mainPid, 10) : mainPid;
 
 	// Relation & privilege check for local categories
-	const hasRelation = options.skipChecks || options.cid || hasTid || await assertRelation(chain[0]);
+	const hasRelation = uid || options.skipChecks || options.cid || hasTid || await assertRelation(chain[0]);
 	const privilege = `topics:${tid ? 'reply' : 'create'}`;
 	const allowed = await privileges.categories.can(privilege, cid, activitypub._constants.uid);
 	if (!hasRelation || !allowed) {
@@ -168,7 +168,7 @@ Notes.assert = async (uid, input, options = { skipChecks: false }) => {
 	}
 
 	await Promise.all([
-		Notes.syncUserInboxes(tid),
+		Notes.syncUserInboxes(tid, uid),
 		unlock(id),
 	]);
 
@@ -282,7 +282,7 @@ Notes.getParentChain = async (uid, input) => {
 	return chain;
 };
 
-Notes.syncUserInboxes = async function (tid) {
+Notes.syncUserInboxes = async function (tid, uid) {
 	const [pids, { cid, mainPid }] = await Promise.all([
 		db.getSortedSetMembers(`tid:${tid}:posts`),
 		topics.getTopicFields(tid, ['tid', 'cid', 'mainPid']),
@@ -291,6 +291,10 @@ Notes.syncUserInboxes = async function (tid) {
 
 	const recipients = await db.getSetsMembers(pids.map(id => `post:${id}:recipients`));
 	const uids = recipients.reduce((set, uids) => new Set([...set, ...uids.map(u => parseInt(u, 10))]), new Set());
+	if (uid) {
+		uids.add(parseInt(uid, 10));
+	}
+
 	const keys = Array.from(uids).map(uid => `uid:${uid}:inbox`);
 	const score = await db.sortedSetScore(`cid:${cid}:tids`, tid);
 
diff --git a/src/controllers/posts.js b/src/controllers/posts.js
index 3b3d5b3b82..2b08558a9a 100644
--- a/src/controllers/posts.js
+++ b/src/controllers/posts.js
@@ -6,6 +6,7 @@ const querystring = require('querystring');
 const meta = require('../meta');
 const posts = require('../posts');
 const privileges = require('../privileges');
+const activitypub = require('../activitypub');
 const utils = require('../utils');
 
 const helpers = require('./helpers');
@@ -18,6 +19,14 @@ postsController.redirectToPost = async function (req, res, next) {
 		return next();
 	}
 
+	// Kickstart note assertion if applicable
+	if (!utils.isNumber(pid) && req.uid) {
+		const exists = await posts.exists(pid);
+		if (!exists) {
+			await activitypub.notes.assert(req.uid, pid);
+		}
+	}
+
 	const [canRead, path] = await Promise.all([
 		privileges.posts.can('topics:read', pid, req.uid),
 		posts.generatePostPath(pid, req.uid),