Index: src/incidence.cpp
===================================================================
--- src/incidence.cpp
+++ src/incidence.cpp
@@ -966,11 +966,13 @@
 
 void Incidence::setSchedulingID(const QString &sid, const QString &uid)
 {
-    d->mSchedulingID = sid;
     if (!uid.isEmpty()) {
         setUid(uid);
     }
-    setFieldDirty(FieldSchedulingId);
+    if (sid != d->mSchedulingID) {
+        d->mSchedulingID = sid;
+        setFieldDirty(FieldSchedulingId);
+    }
 }
 
 QString Incidence::schedulingID() const
Index: src/incidencebase.cpp
===================================================================
--- src/incidencebase.cpp
+++ src/incidencebase.cpp
@@ -227,10 +227,12 @@
 
 void IncidenceBase::setUid(const QString &uid)
 {
-    update();
-    d->mUid = uid;
-    d->mDirtyFields.insert(FieldUid);
-    updated();
+    if (d->mUid != uid) {
+        update();
+        d->mUid = uid;
+        d->mDirtyFields.insert(FieldUid);
+        updated();
+    }
 }
 
 QString IncidenceBase::uid() const