diff --git a/packages/backend/src/GlobalModule.ts b/packages/backend/src/GlobalModule.ts
index 0f69cf93a910..6ae8ccfbb32c 100644
--- a/packages/backend/src/GlobalModule.ts
+++ b/packages/backend/src/GlobalModule.ts
@@ -126,8 +126,8 @@ const $meta: Provider = {
 				const { type, body } = obj.message as GlobalEvents['internal']['payload'];
 				switch (type) {
 					case 'metaUpdated': {
-						for (const key in body) {
-							(meta as any)[key] = (body as any)[key];
+						for (const key in body.after) {
+							(meta as any)[key] = (body.after as any)[key];
 						}
 						meta.proxyAccount = null; // joinなカラムは通常取ってこないので
 						break;
diff --git a/packages/backend/src/core/GlobalEventService.ts b/packages/backend/src/core/GlobalEventService.ts
index f26a306d0e27..afb148025a02 100644
--- a/packages/backend/src/core/GlobalEventService.ts
+++ b/packages/backend/src/core/GlobalEventService.ts
@@ -244,7 +244,7 @@ export interface InternalEventTypes {
 	avatarDecorationCreated: MiAvatarDecoration;
 	avatarDecorationDeleted: MiAvatarDecoration;
 	avatarDecorationUpdated: MiAvatarDecoration;
-	metaUpdated: MiMeta;
+	metaUpdated: { before?: MiMeta; after: MiMeta; };
 	followChannel: { userId: MiUser['id']; channelId: MiChannel['id']; };
 	unfollowChannel: { userId: MiUser['id']; channelId: MiChannel['id']; };
 	updateUserProfile: MiUserProfile;
diff --git a/packages/backend/src/core/MetaService.ts b/packages/backend/src/core/MetaService.ts
index ec630f804e7c..3d88d0aefe97 100644
--- a/packages/backend/src/core/MetaService.ts
+++ b/packages/backend/src/core/MetaService.ts
@@ -52,7 +52,7 @@ export class MetaService implements OnApplicationShutdown {
 			switch (type) {
 				case 'metaUpdated': {
 					this.cache = { // TODO: このあたりのデシリアライズ処理は各modelファイル内に関数としてexportしたい
-						...body,
+						...(body.after),
 						proxyAccount: null, // joinなカラムは通常取ってこないので
 					};
 					break;
@@ -141,7 +141,7 @@ export class MetaService implements OnApplicationShutdown {
 			});
 		}
 
-		this.globalEventService.publishInternalEvent('metaUpdated', updated);
+		this.globalEventService.publishInternalEvent('metaUpdated', { before, after: updated });
 
 		return updated;
 	}
diff --git a/packages/backend/src/core/ReactionService.ts b/packages/backend/src/core/ReactionService.ts
index 062d64f46b7d..6f9fe53937bc 100644
--- a/packages/backend/src/core/ReactionService.ts
+++ b/packages/backend/src/core/ReactionService.ts
@@ -337,10 +337,22 @@ export class ReactionService {
 		//#endregion
 	}
 
+	/**
+	 * - 文字列タイプのレガシーな形式のリアクションを現在の形式に変換する
+	 * - ローカルのリアクションのホストを `@.` にする（`decodeReaction()`の効果）
+	 */
+	@bindThis
+	public convertLegacyReaction(reaction: string): string {
+		reaction = this.decodeReaction(reaction).reaction;
+		if (Object.keys(legacies).includes(reaction)) return legacies[reaction];
+		return reaction;
+	}
+
 	// TODO: 廃止
 	/**
-	 * 文字列タイプのレガシーな形式のリアクションを現在の形式に変換しつつ、
-	 * データベース上には存在する「0個のリアクションがついている」という情報を削除する。
+	 * - 文字列タイプのレガシーな形式のリアクションを現在の形式に変換する
+	 * - ローカルのリアクションのホストを `@.` にする（`decodeReaction()`の効果）
+	 * - データベース上には存在する「0個のリアクションがついている」という情報を削除する
 	 */
 	@bindThis
 	public convertLegacyReactions(reactions: MiNote['reactions']): MiNote['reactions'] {
@@ -353,10 +365,7 @@ export class ReactionService {
 				return count > 0;
 			})
 			.map(([reaction, count]) => {
-				// unchecked indexed access
-				const convertedReaction = legacies[reaction] as string | undefined;
-
-				const key = this.decodeReaction(convertedReaction ?? reaction).reaction;
+				const key = this.convertLegacyReaction(reaction);
 
 				return [key, count] as const;
 			})
@@ -411,11 +420,4 @@ export class ReactionService {
 			host: undefined,
 		};
 	}
-
-	@bindThis
-	public convertLegacyReaction(reaction: string): string {
-		reaction = this.decodeReaction(reaction).reaction;
-		if (Object.keys(legacies).includes(reaction)) return legacies[reaction];
-		return reaction;
-	}
 }
diff --git a/packages/backend/src/core/ReactionsBufferingService.ts b/packages/backend/src/core/ReactionsBufferingService.ts
index b1a197feeb17..b4207c51062c 100644
--- a/packages/backend/src/core/ReactionsBufferingService.ts
+++ b/packages/backend/src/core/ReactionsBufferingService.ts
@@ -11,22 +11,48 @@ import { bindThis } from '@/decorators.js';
 import type { MiUser, NotesRepository } from '@/models/_.js';
 import type { Config } from '@/config.js';
 import { PER_NOTE_REACTION_USER_PAIR_CACHE_MAX } from '@/const.js';
+import type { GlobalEvents } from '@/core/GlobalEventService.js';
+import type { OnApplicationShutdown } from '@nestjs/common';
 
 const REDIS_DELTA_PREFIX = 'reactionsBufferDeltas';
 const REDIS_PAIR_PREFIX = 'reactionsBufferPairs';
 
 @Injectable()
-export class ReactionsBufferingService {
+export class ReactionsBufferingService implements OnApplicationShutdown {
 	constructor(
 		@Inject(DI.config)
 		private config: Config,
 
+		@Inject(DI.redisForSub)
+		private redisForSub: Redis.Redis,
+
 		@Inject(DI.redisForReactions)
 		private redisForReactions: Redis.Redis, // TODO: 専用のRedisインスタンスにする
 
 		@Inject(DI.notesRepository)
 		private notesRepository: NotesRepository,
 	) {
+		this.redisForSub.on('message', this.onMessage);
+	}
+
+	@bindThis
+	private async onMessage(_: string, data: string) {
+		const obj = JSON.parse(data);
+
+		if (obj.channel === 'internal') {
+			const { type, body } = obj.message as GlobalEvents['internal']['payload'];
+			switch (type) {
+				case 'metaUpdated': {
+					// リアクションバッファリングが有効→無効になったら即bake
+					if (body.before != null && body.before.enableReactionsBuffering && !body.after.enableReactionsBuffering) {
+						this.bake();
+					}
+					break;
+				}
+				default:
+					break;
+			}
+		}
 	}
 
 	@bindThis
@@ -159,4 +185,27 @@ export class ReactionsBufferingService {
 				.execute();
 		}
 	}
+
+	@bindThis
+	public mergeReactions(src: MiNote['reactions'], delta: Record<string, number>): MiNote['reactions'] {
+		const reactions = { ...src };
+		for (const [name, count] of Object.entries(delta)) {
+			if (reactions[name] != null) {
+				reactions[name] += count;
+			} else {
+				reactions[name] = count;
+			}
+		}
+		return reactions;
+	}
+
+	@bindThis
+	public dispose(): void {
+		this.redisForSub.off('message', this.onMessage);
+	}
+
+	@bindThis
+	public onApplicationShutdown(signal?: string | undefined): void {
+		this.dispose();
+	}
 }
diff --git a/packages/backend/src/core/entities/NoteEntityService.ts b/packages/backend/src/core/entities/NoteEntityService.ts
index e636d9973f4c..6e12cc85ae0e 100644
--- a/packages/backend/src/core/entities/NoteEntityService.ts
+++ b/packages/backend/src/core/entities/NoteEntityService.ts
@@ -16,25 +16,12 @@ import { bindThis } from '@/decorators.js';
 import { DebounceLoader } from '@/misc/loader.js';
 import { IdService } from '@/core/IdService.js';
 import { ReactionsBufferingService } from '@/core/ReactionsBufferingService.js';
-import { MetaService } from '@/core/MetaService.js';
 import type { OnModuleInit } from '@nestjs/common';
 import type { CustomEmojiService } from '../CustomEmojiService.js';
 import type { ReactionService } from '../ReactionService.js';
 import type { UserEntityService } from './UserEntityService.js';
 import type { DriveFileEntityService } from './DriveFileEntityService.js';
 
-function mergeReactions(src: Record<string, number>, delta: Record<string, number>) {
-	const reactions = { ...src };
-	for (const [name, count] of Object.entries(delta)) {
-		if (reactions[name] != null) {
-			reactions[name] += count;
-		} else {
-			reactions[name] = count;
-		}
-	}
-	return reactions;
-}
-
 @Injectable()
 export class NoteEntityService implements OnModuleInit {
 	private userEntityService: UserEntityService;
@@ -329,12 +316,7 @@ export class NoteEntityService implements OnModuleInit {
 			: this.meta.enableReactionsBuffering
 				? await this.reactionsBufferingService.get(note.id)
 				: { deltas: {}, pairs: [] };
-		const reactions = mergeReactions(this.reactionService.convertLegacyReactions(note.reactions), bufferedReactions.deltas ?? {});
-		for (const [name, count] of Object.entries(reactions)) {
-			if (count <= 0) {
-				delete reactions[name];
-			}
-		}
+		const reactions = this.reactionService.convertLegacyReactions(this.reactionsBufferingService.mergeReactions(note.reactions, bufferedReactions.deltas ?? {}));
 
 		const reactionAndUserPairCache = note.reactionAndUserPairCache.concat(bufferedReactions.pairs.map(x => x.join('/')));
 
@@ -452,7 +434,7 @@ export class NoteEntityService implements OnModuleInit {
 
 			for (const note of notes) {
 				if (note.renote && (note.text == null && note.fileIds.length === 0)) { // pure renote
-					const reactionsCount = Object.values(mergeReactions(note.renote.reactions, bufferedReactions?.get(note.renote.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
+					const reactionsCount = Object.values(this.reactionsBufferingService.mergeReactions(note.renote.reactions, bufferedReactions?.get(note.renote.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
 					if (reactionsCount === 0) {
 						myReactionsMap.set(note.renote.id, null);
 					} else if (reactionsCount <= note.renote.reactionAndUserPairCache.length + (bufferedReactions?.get(note.renote.id)?.pairs.length ?? 0)) {
@@ -468,7 +450,7 @@ export class NoteEntityService implements OnModuleInit {
 					}
 				} else {
 					if (note.id < oldId) {
-						const reactionsCount = Object.values(mergeReactions(note.reactions, bufferedReactions?.get(note.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
+						const reactionsCount = Object.values(this.reactionsBufferingService.mergeReactions(note.reactions, bufferedReactions?.get(note.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
 						if (reactionsCount === 0) {
 							myReactionsMap.set(note.id, null);
 						} else if (reactionsCount <= note.reactionAndUserPairCache.length + (bufferedReactions?.get(note.id)?.pairs.length ?? 0)) {