diff --git a/cassandane/Cassandane/Cyrus/Caldav.pm b/cassandane/Cassandane/Cyrus/Caldav.pm
index 42e3e91c86..c21af31547 100644
--- a/cassandane/Cassandane/Cyrus/Caldav.pm
+++ b/cassandane/Cassandane/Cyrus/Caldav.pm
@@ -47,6 +47,7 @@ use Net::DAVTalk::XMLParser;
 use File::Basename;
 use Data::Dumper;
 use Text::VCardFast;
+use Cwd qw(abs_path);
 
 use lib '.';
 use base qw(Cassandane::Cyrus::TestCase);
@@ -6031,4 +6032,44 @@ EOF
     $self->assert_not_null($valarms[0]{properties}{uid});
 }
 
+sub test_freebusy_overrides
+    :min_version_3_9 :needs_component_httpd
+{
+    my ($self) = @_;
+
+    my $CalDAV = $self->{caldav};
+
+    my $ical = <<EOF;
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Apple Inc.//Mac OS X 10.9.5//EN
+CALSCALE:GREGORIAN
+BEGIN:VEVENT
+RECURRENCE-ID:20230909T160000Z
+DTSTART:20230101T160000Z
+DURATION:PT1H
+UID:40ce7797-98ed-4185-a364-a95bb01ea2fe
+SUMMARY:recur1
+END:VEVENT
+BEGIN:VEVENT
+RECURRENCE-ID:20231231T160000Z
+DTSTART:20231231T160000Z
+DURATION:PT2H
+UID:40ce7797-98ed-4185-a364-a95bb01ea2fe
+SUMMARY:recur2
+END:VEVENT
+END:VCALENDAR
+EOF
+
+    $CalDAV->Request('PUT', '/dav/calendars/user/cassandane/Default/test.ics',
+        $ical, 'Content-Type' => 'text/calendar');
+
+    my ($data, $errors) = $CalDAV->GetFreeBusy('Default');
+    $self->assert_str_equals('2023-01-01T16:00:00', $data->[0]{start});
+    $self->assert_str_equals('PT1H', $data->[0]{duration});
+    $self->assert_str_equals('2023-12-31T16:00:00', $data->[1]{start});
+    $self->assert_str_equals('PT2H', $data->[1]{duration});
+    $self->assert_num_equals(2, scalar @$data);
+}
+
 1;
diff --git a/imap/ical_support.c b/imap/ical_support.c
index 3204f1f67b..745488a717 100644
--- a/imap/ical_support.c
+++ b/imap/ical_support.c
@@ -1342,6 +1342,7 @@ icalrecurrenceset_get_utc_timespan(icalcomponent *ical,
     struct icalperiodtype span;
     icalcomponent *comp = icalcomponent_get_first_component(ical, kind);
     unsigned recurring = 0;
+    unsigned n_recurid = 0;
 
     /* Initialize span to be nothing */
     span.start = icaltime_from_timet_with_zone(caldav_eternity, 0, NULL);
@@ -1426,6 +1427,10 @@ icalrecurrenceset_get_utc_timespan(icalcomponent *ical,
             ptrarray_fini(&detached_rrules);
         }
 
+        /* Count recurrence-ids */
+        if (icalcomponent_get_first_property(comp, ICAL_RECURRENCEID_PROPERTY))
+            if (n_recurid < UINT_MAX) n_recurid++;
+
         /* Check our dtstart and dtend against span */
         if (icaltime_compare(period.start, span.start) < 0)
             memcpy(&span.start, &period.start, sizeof(struct icaltimetype));
@@ -1438,6 +1443,10 @@ icalrecurrenceset_get_utc_timespan(icalcomponent *ical,
 
     } while ((comp = icalcomponent_get_next_component(ical, kind)));
 
+    /* There might be more than one recurrence override without main component */
+    if (!recurring && n_recurid >= 2)
+        recurring = 1;
+
     if (is_recurring) *is_recurring = recurring;
 
     return span;