diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04e7017001..bcfd7cebcb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -36,6 +36,7 @@
 - Fix: トークンのないプラグインをアンインストールするときにエラーが出ないように
 - Fix: 投稿通知がオンでもダイレクト投稿はユーザーに通知されないようにされました
 - Fix: ユーザタイムラインの「ノート」選択時にリノートが混ざり込んでしまうことがある問題の修正 #12306
+- Fix: LTLに特定条件下にてチャンネルへの投稿が混ざり込む現象を修正
 - Fix: ActivityPub: 追加情報のカスタム絵文字がユーザー情報のtagに含まれない問題を修正
 - Fix: ActivityPubに関するセキュリティの向上
 - Fix: 非公開の投稿に対して返信できないように
diff --git a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
index b1fa34cc9e..02f43d0712 100644
--- a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
@@ -180,8 +180,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				redisTimeline.push(...timeline);
 			}
 
+			// fallback to db
 			if (redisTimeline.length === 0) {
-				// fallback to db
+				if (!serverSettings.enableFanoutTimelineDbFallback) return [];
+
 				return await this.getFromDb({
 					untilId,
 					sinceId,
diff --git a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
index 24343664af..74ca9cd665 100644
--- a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
@@ -155,8 +155,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				redisTimeline.push(...timeline);
 			}
 
+			// fallback to db
 			if (redisTimeline.length === 0) {
-				// fallback to db
+				if (!serverSettings.enableFanoutTimelineDbFallback) return [];
+
 				return await this.getFromDb({
 					untilId,
 					sinceId,
@@ -185,7 +187,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 	}, me: MiLocalUser | null) {
 		const query = this.queryService.makePaginationQuery(this.notesRepository.createQueryBuilder('note'),
 			ps.sinceId, ps.untilId)
-			.andWhere('(note.visibility = \'public\') AND (note.userHost IS NULL)')
+			.andWhere('(note.visibility = \'public\') AND (note.userHost IS NULL) AND (note.channelId IS NULL)')
 			.innerJoinAndSelect('note.user', 'user')
 			.leftJoinAndSelect('note.reply', 'reply')
 			.leftJoinAndSelect('note.renote', 'renote')
diff --git a/packages/backend/src/server/api/endpoints/notes/timeline.ts b/packages/backend/src/server/api/endpoints/notes/timeline.ts
index 52e645d932..7091f44b48 100644
--- a/packages/backend/src/server/api/endpoints/notes/timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/timeline.ts
@@ -142,8 +142,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				redisTimeline.push(...timeline);
 			}
 
+			// fallback to db
 			if (redisTimeline.length === 0) {
-				// fallback to db
+				if (!serverSettings.enableFanoutTimelineDbFallback) return [];
+
 				return await this.getFromDb({
 					untilId,
 					sinceId,
diff --git a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
index 2b22dae29f..0b9c5a9dc1 100644
--- a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
@@ -161,8 +161,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				redisTimeline.push(...timeline);
 			}
 
+			// fallback to db
 			if (redisTimeline.length === 0) {
-				// fallback to db
+				if (!serverSettings.enableFanoutTimelineDbFallback) return [];
+
 				return await this.getFromDb(list, {
 					untilId,
 					sinceId,
diff --git a/packages/backend/src/server/api/stream/channels/local-timeline.ts b/packages/backend/src/server/api/stream/channels/local-timeline.ts
index 9dd05b9b08..1388f186ff 100644
--- a/packages/backend/src/server/api/stream/channels/local-timeline.ts
+++ b/packages/backend/src/server/api/stream/channels/local-timeline.ts
@@ -52,7 +52,7 @@ class LocalTimelineChannel extends Channel {
 
 		if (note.user.host !== null) return;
 		if (note.visibility !== 'public') return;
-		if (note.channelId != null && !this.followingChannels.has(note.channelId)) return;
+		if (note.channelId != null) return;
 
 		// 関係ない返信は除外
 		if (note.reply && this.user && !this.following[note.userId]?.withReplies && !this.withReplies) {