diff --git a/src/activitypub/helpers.js b/src/activitypub/helpers.js
index 5dff8c0b00..b36f18166b 100644
--- a/src/activitypub/helpers.js
+++ b/src/activitypub/helpers.js
@@ -197,6 +197,9 @@ Helpers.resolveLocalId = async (input) => {
 				case 'post':
 					return { type: 'post', id: value, ...activityData };
 
+				case 'topic':
+					return { type: 'topic', id: value, ...activityData };
+
 				case 'cid':
 				case 'category':
 					return { type: 'category', id: value, ...activityData };
diff --git a/src/activitypub/notes.js b/src/activitypub/notes.js
index 3ca30b7aa5..582832bcc1 100644
--- a/src/activitypub/notes.js
+++ b/src/activitypub/notes.js
@@ -82,18 +82,33 @@ Notes.assert = async (uid, input, options = { skipChecks: false }) => {
 			const { tid } = context;
 			return { tid, count: 0 };
 		} else if (context.context) {
-			chain = Array.from(await activitypub.contexts.getItems(uid, context.context, { input }));
-			if (chain && chain.length) {
-				// Deduplicate by id (just in case, also a buggy NodeBB impl. sent dupes)
-				const ids = new Set();
-				chain = chain.filter((item) => {
-					const seen = ids.has(item.pid);
-					ids.add(item.pid);
-					return !seen;
-				});
+			const { type, id: tid } = await activitypub.helpers.resolveLocalId(context.context);
+			if (!type === 'topic') {
+				chain = Array.from(await activitypub.contexts.getItems(uid, context.context, { input }));
+				if (chain && chain.length) {
+					// Deduplicate by id (just in case, also a buggy NodeBB impl. sent dupes)
+					const ids = new Set();
+					chain = chain.filter((item) => {
+						const seen = ids.has(item.pid);
+						ids.add(item.pid);
+						return !seen;
+					});
 
-				// Context resolves, use in later topic creation
-				context = context.context;
+					// Context resolves, use in later topic creation
+					context = context.context;
+				}
+			} else {
+				// Local context, get local posts
+				const mainPid = await topics.getTopicField(tid, 'mainPid');
+				const pids = await db.getSortedSetMembers(`tid:${tid}:posts`);
+				pids.unshift(mainPid);
+				chain = await posts.getPostsData(pids);
+
+				// Add received object to chain if not present already
+				if (!pids.includes(input.id)) {
+					const mocked = await activitypub.mocks.post(input);
+					chain.push(mocked);
+				}
 			}
 		} else {
 			context = undefined;