diff --git a/radicale/tests/static/event_issue2151.ics b/radicale/tests/static/event_issue2151.ics
new file mode 100644
index 00000000..a72d3731
--- /dev/null
+++ b/radicale/tests/static/event_issue2151.ics
@@ -0,0 +1,116 @@
+BEGIN:VCALENDAR
+PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
+VERSION:2.0
+BEGIN:VTIMEZONE
+TZID:W. Europe Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+CREATED:20260605T085814Z
+LAST-MODIFIED:20260605T100722Z
+DTSTAMP:20260605T100722Z
+UID:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+SUMMARY:Billings-task-setting follow-up series
+PRIORITY:5
+STATUS:CONFIRMED
+ORGANIZER;CN=XXXXXXXX XXXXX:mailto:XXXXXXX@XXXXXXXXXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XX;PARTSTAT=ACCEPTED;ROLE=REQ-PARTICIPANT:mailto:XX@XXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XXXXXXXX XXXXXXX;PARTSTAT=NEEDS-ACTION;ROLE=REQ-PARTICIPANT:mailto:XXXXXXXXX@XXXXXXXXXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XXXXXX XXXXXXXX;PARTSTAT=NEEDS-ACTION;ROLE=REQ-PARTICIPANT:mailto:XXXXXXXXXX@XXXXXXXXXXXXXX.XXX
+EXDATE:20260403T110000
+RRULE:FREQ=WEEKLY;BYDAY=FR;UNTIL=20260731T090000Z
+X-MOZ-LASTACK:20260605T100722Z
+DTSTART;TZID=W. Europe Standard Time:20260123T110000
+DTEND;TZID=W. Europe Standard Time:20260123T120000
+CLASS:PUBLIC
+DESCRIPTION;LANGUAGE=de-DE:Serie war letzte Woche ausgelaufen\n\nMicrosoft Teams meeting details redacted.\n
+LOCATION;LANGUAGE=de-DE:Microsoft Teams-Besprechung
+SEQUENCE:0
+TRANSP:OPAQUE
+X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
+X-MICROSOFT-CDO-APPT-SEQUENCE:0
+X-MICROSOFT-CDO-BUSYSTATUS:TENTATIVE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:1
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-OWNERAPPTID:XXXXXXXXXX
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-ISRESPONSEREQUESTED:TRUE
+X-MICROSOFT-LOCATIONDISPLAYNAME:Microsoft Teams-Besprechung
+X-MICROSOFT-LOCATIONS:[{"DisplayName":"Microsoft Teams-Besprechung"\,"LocationAnnotation":""\,"LocationUri":""\,"LocationStreet":""\,"LocationCity":""\,"LocationState":""\,"LocationCountry":""\,"LocationPostalCode":""\,"LocationFullAddress":""}]
+X-MICROSOFT-LOCATIONSOURCE:None
+X-MICROSOFT-ONLINEMEETINGINFORMATION:{"OnlineMeetingChannelId":null\,"OnlineMeetingProvider":3}
+X-MICROSOFT-REQUESTEDATTENDANCEMODE:DEFAULT
+X-MICROSOFT-SCHEDULINGSERVICEUPDATEURL:REDACTED
+X-MICROSOFT-SKYPETEAMSMEETINGURL:REDACTED
+X-MICROSOFT-SKYPETEAMSPROPERTIES:REDACTED
+X-MOZ-GENERATION:17
+X-MOZ-INVITED-ATTENDEE:mailto:XX@XXXXXXX.XXX
+X-MOZ-RECEIVED-DTSTAMP:20260123T100333Z
+X-MOZ-RECEIVED-SEQUENCE:0
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER:-PT5M
+DESCRIPTION:Mozilla Standardbeschreibung
+END:VALARM
+END:VEVENT
+BEGIN:VEVENT
+CREATED:20260605T085814Z
+LAST-MODIFIED:20260130T093740Z
+DTSTAMP:20260130T093740Z
+UID:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+SUMMARY:Billings-task-setting follow-up series
+PRIORITY:5
+STATUS:CONFIRMED
+RECURRENCE-ID;TZID=W. Europe Standard Time:20260130T110000
+ORGANIZER;CN=XXXXXXXX XXXXX:mailto:XXXXXXX@XXXXXXXXXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XXXXXXXX XXXXXXX;PARTSTAT=NEEDS-ACTION;ROLE=REQ-PARTICIPANT:mailto:XXXXXXXXX@XXXXXXXXXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XXXXXX XXXXXXXX;PARTSTAT=NEEDS-ACTION;ROLE=REQ-PARTICIPANT:mailto:XXXXXXXXXX@XXXXXXXXXXXXXX.XXX
+ATTENDEE;RSVP=TRUE;CN=XX;PARTSTAT=ACCEPTED;ROLE=REQ-PARTICIPANT:mailto:XX@XXXXXXX.XXX
+DTSTART;TZID=W. Europe Standard Time:20260130T103000
+DTEND;TZID=W. Europe Standard Time:20260130T113000
+CLASS:PUBLIC
+DESCRIPTION:Serie war letzte Woche ausgelaufen\n\nMicrosoft Teams meeting details redacted.\n
+LOCATION:Microsoft Teams-Besprechung
+SEQUENCE:1
+TRANSP:OPAQUE
+X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
+X-MICROSOFT-CDO-APPT-SEQUENCE:1
+X-MICROSOFT-CDO-BUSYSTATUS:TENTATIVE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:3
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-OWNERAPPTID:XXXXXXXXXX
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-ISRESPONSEREQUESTED:TRUE
+X-MICROSOFT-LOCATIONDISPLAYNAME:Microsoft Teams-Besprechung
+X-MICROSOFT-LOCATIONS:[{"DisplayName":"Microsoft Teams-Besprechung"\,"LocationAnnotation":""\,"LocationUri":""\,"LocationStreet":""\,"LocationCity":""\,"LocationState":""\,"LocationCountry":""\,"LocationPostalCode":""\,"LocationFullAddress":""}]
+X-MICROSOFT-LOCATIONSOURCE:None
+X-MICROSOFT-ONLINEMEETINGINFORMATION:{"OnlineMeetingChannelId":null\,"OnlineMeetingProvider":3}
+X-MICROSOFT-REQUESTEDATTENDANCEMODE:DEFAULT
+X-MICROSOFT-SCHEDULINGSERVICEUPDATEURL:REDACTED
+X-MICROSOFT-SKYPETEAMSMEETINGURL:REDACTED
+X-MICROSOFT-SKYPETEAMSPROPERTIES:REDACTED
+X-MOZ-GENERATION:0
+X-MOZ-RECEIVED-DTSTAMP:20260130T093205Z
+X-MOZ-RECEIVED-SEQUENCE:1
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER:-PT5M
+DESCRIPTION:Mozilla Standardbeschreibung
+END:VALARM
+END:VEVENT
+END:VCALENDAR
diff --git a/radicale/tests/test_base.py b/radicale/tests/test_base.py
index 10f8b40d..733031e3 100644
--- a/radicale/tests/test_base.py
+++ b/radicale/tests/test_base.py
@@ -273,6 +273,12 @@ permissions: RrWw""")
         event = get_file_content("event_exdate_without_rrule.ics")
         self.put("/calendar.ics/event.ics", event)
 
+    def test_add_event_with_issue2151(self) -> None:
+        """Test event of issue#2151."""
+        self.mkcalendar("/calendar.ics/")
+        event = get_file_content("event_issue2151.ics")
+        self.put("/calendar.ics/event_issue2151.ics", event)
+
     def test_add_todo(self) -> None:
         """Add a todo."""
         self.mkcalendar("/calendar.ics/")