diff --git a/src/main/java/io/redlink/more/data/repository/StudyRepository.java b/src/main/java/io/redlink/more/data/repository/StudyRepository.java
index 7e5c415..dc085c6 100644
--- a/src/main/java/io/redlink/more/data/repository/StudyRepository.java
+++ b/src/main/java/io/redlink/more/data/repository/StudyRepository.java
@@ -260,7 +260,7 @@ private void updateParticipantStatus(long studyId, int groupId, int participantI
 
         if ("active".equals(newStatus)) {
             start = Timestamp.from(
-                    SchedulerUtils.shiftStartIfObservationAlreadyStarted(Instant.now(), listObservations(studyId, groupId, participantId, true))
+                    SchedulerUtils.shiftStartIfObservationAlreadyEnded(Instant.now(), listObservations(studyId, groupId, participantId, true))
             );
         }
 
diff --git a/src/main/java/io/redlink/more/data/schedule/SchedulerUtils.java b/src/main/java/io/redlink/more/data/schedule/SchedulerUtils.java
index f040233..dbdad23 100644
--- a/src/main/java/io/redlink/more/data/schedule/SchedulerUtils.java
+++ b/src/main/java/io/redlink/more/data/schedule/SchedulerUtils.java
@@ -35,8 +35,6 @@ public static List<Pair<Instant, Instant>> parseToObservationSchedulesForRelativ
 
         List<Pair<Instant, Instant>> events = new ArrayList<>();
 
-        start = shiftStartIfNecessary(start);
-
         Pair<Instant, Instant> currentEvt = Pair.of(toInstant(event.getDtstart(), start), toInstant(event.getDtend(), start));
 
         if(event.getRrrule() != null) {
@@ -57,11 +55,6 @@ public static List<Pair<Instant, Instant>> parseToObservationSchedulesForRelativ
         return events;
     }
 
-    private static Instant shiftStartIfNecessary(Instant start) {
-        // TODO
-        return start;
-    }
-
     private static Instant toInstant(RelativeDate date, Instant start) {
         return ZonedDateTime.ofInstant(start.plus(date.getOffset().getValue() - 1L, date.getOffset().getUnit().toTemporalUnit()), date.getZoneId())
                 .withHour(date.getHours())
@@ -98,7 +91,7 @@ public static List<Pair<Instant, Instant>> parseToObservationSchedules(ScheduleE
         }
     }
 
-    public static Instant shiftStartIfObservationAlreadyStarted(Instant start, List<Observation> observations) {
+    public static Instant shiftStartIfObservationAlreadyEnded(Instant start, List<Observation> observations) {
         // returns start date, if now event ends before, otherwise start date + 1 day
         return observations.stream()
                 .map(Observation::observationSchedule)
@@ -107,7 +100,7 @@ public static Instant shiftStartIfObservationAlreadyStarted(Instant start, List<
                 .filter(relativeDate -> relativeDate.getOffset().getValue() == 1)
                 .map(relativeDate -> start.atZone(relativeDate.getZoneId()).withHour(relativeDate.getHours()).withMinute(relativeDate.getMinutes()).withSecond(0).withNano(0).toInstant())
                 .filter(instant -> {
-                    return  instant.isBefore(start.plus(1, ChronoUnit.HOURS));
+                    return  instant.isBefore(start);
                 })
                 .map(instant -> start.atZone(ZoneId.systemDefault()).withHour(0).withMinute(0).plusDays(1).toInstant())
                 .findFirst()
diff --git a/src/main/java/io/redlink/more/data/service/CalendarService.java b/src/main/java/io/redlink/more/data/service/CalendarService.java
index 27741d1..3409014 100644
--- a/src/main/java/io/redlink/more/data/service/CalendarService.java
+++ b/src/main/java/io/redlink/more/data/service/CalendarService.java
@@ -17,7 +17,7 @@
 import java.util.Optional;
 import java.util.TimeZone;
 
-import static io.redlink.more.data.schedule.SchedulerUtils.shiftStartIfObservationAlreadyStarted;
+import static io.redlink.more.data.schedule.SchedulerUtils.shiftStartIfObservationAlreadyEnded;
 
 @Service
 public class CalendarService {
@@ -39,7 +39,7 @@ public Optional<String> getICalendarString(Long studyId) {
             iCalEvent.setDateEnd(Date.from(study.endDate().atStartOfDay(TimeZone.getDefault().toZoneId()).toInstant()), false);
             ical.addEvent(iCalEvent);
 
-            final Instant start = shiftStartIfObservationAlreadyStarted(
+            final Instant start = shiftStartIfObservationAlreadyEnded(
                     study.plannedStartDate().atStartOfDay(ZoneId.systemDefault()).toInstant(),
                     study.observations()
             );
diff --git a/src/test/java/io/redlink/more/data/schedule/SchedulerUtilsTest.java b/src/test/java/io/redlink/more/data/schedule/SchedulerUtilsTest.java
index 9103e86..b740f87 100644
--- a/src/test/java/io/redlink/more/data/schedule/SchedulerUtilsTest.java
+++ b/src/test/java/io/redlink/more/data/schedule/SchedulerUtilsTest.java
@@ -25,7 +25,7 @@
 import java.util.Arrays;
 import java.util.List;
 
-import static io.redlink.more.data.schedule.SchedulerUtils.shiftStartIfObservationAlreadyStarted;
+import static io.redlink.more.data.schedule.SchedulerUtils.shiftStartIfObservationAlreadyEnded;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -392,13 +392,13 @@ void testRelativeEventShift() {
         when(observationDay1At13.observationSchedule()).thenReturn(day1At13);
         when(observationDay2At10.observationSchedule()).thenReturn(day2At10);
 
-        Instant s1 = shiftStartIfObservationAlreadyStarted(start, List.of(observationDay1At10, observationDay1At12, observationDay2At10));
+        Instant s1 = shiftStartIfObservationAlreadyEnded(start, List.of(observationDay1At10, observationDay1At12, observationDay2At10));
         Assertions.assertNotEquals(s1.toEpochMilli(), start.toEpochMilli());
 
-        Instant s2 = shiftStartIfObservationAlreadyStarted(start, List.of(observationDay1At12, observationDay2At10));
-        Assertions.assertNotEquals(s2.toEpochMilli(), start.toEpochMilli());
+        Instant s2 = shiftStartIfObservationAlreadyEnded(start, List.of(observationDay1At12, observationDay2At10));
+        Assertions.assertEquals(s2.toEpochMilli(), start.toEpochMilli());
 
-        Instant s3 = shiftStartIfObservationAlreadyStarted(start, List.of(observationDay1At13, observationDay2At10));
+        Instant s3 = shiftStartIfObservationAlreadyEnded(start, List.of(observationDay1At13, observationDay2At10));
         Assertions.assertEquals(s3.toEpochMilli(), start.toEpochMilli());
     }