diff --git a/packages/backend/src/core/entities/UserEntityService.ts b/packages/backend/src/core/entities/UserEntityService.ts
index b822c5dce4..4e2f0317dd 100644
--- a/packages/backend/src/core/entities/UserEntityService.ts
+++ b/packages/backend/src/core/entities/UserEntityService.ts
@@ -412,7 +412,7 @@ export class UserEntityService implements OnModuleInit {
 					userId: meId,
 					targetUserId: user.id,
 				}).then(row => row?.memo ?? null),
-				moderationNote: iAmModerator ? profile!.moderationNote : null,
+				moderationNote: iAmModerator ? (profile!.moderationNote ?? '') : null,
 			} : {}),
 
 			...(opts.detail && isMe ? {
diff --git a/packages/backend/src/server/api/endpoints/admin/show-user.ts b/packages/backend/src/server/api/endpoints/admin/show-user.ts
index 9d19efbbcf..42229c8f23 100644
--- a/packages/backend/src/server/api/endpoints/admin/show-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/show-user.ts
@@ -80,7 +80,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> {
 				isSilenced: isSilenced,
 				isSuspended: user.isSuspended,
 				lastActiveDate: user.lastActiveDate,
-				moderationNote: profile.moderationNote,
+				moderationNote: profile.moderationNote ?? '',
 				signins,
 				policies: await this.roleService.getUserPolicies(user.id),
 				roles: await this.roleEntityService.packMany(roles, me),