diff --git a/lib/__tests__/calendar-participants.test.ts b/lib/__tests__/calendar-participants.test.ts
index af706eff..918b26c5 100644
--- a/lib/__tests__/calendar-participants.test.ts
+++ b/lib/__tests__/calendar-participants.test.ts
@@ -282,7 +282,7 @@ describe('buildParticipantMap', () => {
     expect(org).toBeDefined();
     expect(org!.name).toBe('Alice');
     expect(org!.email).toBe('alice@example.com');
-    expect(org!.roles).toEqual({ owner: true, attendee: true });
+    expect(org!.roles).toEqual({ owner: true });
     expect(org!.participationStatus).toBe('accepted');
     expect(org!.scheduleAgent).toBe('server');
     // sendTo is retired in draft-ietf-calext-jscalendarbis; the scheduling
@@ -312,7 +312,7 @@ describe('buildParticipantMap', () => {
     expect(Object.keys(map)).toHaveLength(1);
     const org = Object.values(map)[0];
     expect(org).toBeDefined();
-    expect(org.roles).toEqual({ owner: true, attendee: true });
+    expect(org.roles).toEqual({ owner: true });
   });
 
   it('sets @type to Participant for all entries', () => {
diff --git a/lib/calendar-participants.ts b/lib/calendar-participants.ts
index 7a71c034..5ffaaf49 100644
--- a/lib/calendar-participants.ts
+++ b/lib/calendar-participants.ts
@@ -115,7 +115,10 @@ export function buildParticipantMap(
     name: organizer.name,
     email: organizer.email,
     calendarAddress: `mailto:${organizer.email}`,
-    roles: { owner: true, attendee: true },
+    // owner only, NOT attendee: with roles.attendee set, Stalwart's server-side
+    // scheduling emits the organizer as an ATTENDEE line in addition to the
+    // ORGANIZER line, so the recipient sees the organizer listed twice.
+    roles: { owner: true },
     participationStatus: 'accepted',
     scheduleAgent: 'server',
     expectReply: false,
diff --git a/package-lock.json b/package-lock.json
index 0763801f..eca1c271 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6223,6 +6223,7 @@
       "version": "2.3.2",
       "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
       "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
       "hasInstallScript": true,
       "license": "MIT",
       "optional": true,
@@ -7903,6 +7904,17 @@
         }
       }
     },
+    "node_modules/next-intl/node_modules/@swc/helpers": {
+      "version": "0.5.23",
+      "resolved": "https://registry.npmjs.org/@swc/helpers/-/helpers-0.5.23.tgz",
+      "integrity": "sha512-5lSsMOTXURePglDfvuAQUqkGek9Hg2kksOYay2m0+XR++b2NWYL/4sWyuvVBIs8oKnJaxkdi9whaL/sqN13afw==",
+      "license": "Apache-2.0",
+      "optional": true,
+      "peer": true,
+      "dependencies": {
+        "tslib": "^2.8.0"
+      }
+    },
     "node_modules/next/node_modules/postcss": {
       "version": "8.4.31",
       "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.4.31.tgz",