diff --git a/src/gmp/commands/wizard.js b/src/gmp/commands/wizard.js
index 8b18062e88..2943bfb577 100644
--- a/src/gmp/commands/wizard.js
+++ b/src/gmp/commands/wizard.js
@@ -178,7 +178,7 @@ class WizardCommand extends HttpCommand {
       event_data_quick_task_fields,
     );
 
-    event_data['event_data:start_day'] = start_date.day();
+    event_data['event_data:start_day'] = start_date.date();
     event_data['event_data:start_month'] = start_date.month() + 1;
     event_data['event_data:start_year'] = start_date.year();
 
diff --git a/src/gmp/models/event.js b/src/gmp/models/event.js
index 3a1d814c9d..a413fcb494 100644
--- a/src/gmp/models/event.js
+++ b/src/gmp/models/event.js
@@ -3,7 +3,6 @@
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
 
-
 import ical from 'ical.js';
 
 import {v4 as uuid} from 'uuid';
@@ -305,7 +304,8 @@ class Event {
   }
 
   get duration() {
-    return createDuration({...this.event.duration});
+    const {weeks, ...durationWithoutWeeks} = this.event.duration;
+    return createDuration(durationWithoutWeeks);
   }
 
   get durationInSeconds() {