diff --git a/packages/backend/src/core/NoteCreateService.ts b/packages/backend/src/core/NoteCreateService.ts
index 39c2a8938..52e8795c3 100644
--- a/packages/backend/src/core/NoteCreateService.ts
+++ b/packages/backend/src/core/NoteCreateService.ts
@@ -810,7 +810,7 @@ export class NoteCreateService implements OnApplicationShutdown {
 
 					const muted = isUserRelated(note, userIdsWhoMeMuting);
 
-					if (!isThreadMuted || !muted) {
+					if (!isThreadMuted && !muted) {
 						nm.push(data.reply.userId, 'reply');
 						this.globalEventService.publishMainStream(data.reply.userId, 'reply', noteObj);
 
@@ -845,7 +845,7 @@ export class NoteCreateService implements OnApplicationShutdown {
 
 					const muted = isUserRelated(note, userIdsWhoMeMuting);
 
-					if (!isThreadMuted || !muted) {
+					if (!isThreadMuted && !muted) {
 						nm.push(data.renote.userId, type);
 					}
 				}
diff --git a/packages/backend/src/core/NoteEditService.ts b/packages/backend/src/core/NoteEditService.ts
index d7a79920e..bfadb1d18 100644
--- a/packages/backend/src/core/NoteEditService.ts
+++ b/packages/backend/src/core/NoteEditService.ts
@@ -627,7 +627,7 @@ export class NoteEditService implements OnApplicationShutdown {
 
 					const muted = isUserRelated(note, userIdsWhoMeMuting);
 
-					if (!isThreadMuted || !muted) {
+					if (!isThreadMuted && !muted) {
 						nm.push(data.reply.userId, 'reply');
 						this.globalEventService.publishMainStream(data.reply.userId, 'reply', noteObj);
 
@@ -662,7 +662,7 @@ export class NoteEditService implements OnApplicationShutdown {
 
 					const muted = isUserRelated(note, userIdsWhoMeMuting);
 
-					if (!isThreadMuted || !muted) {
+					if (!isThreadMuted && !muted) {
 						nm.push(data.renote.userId, type);
 					}
 				}