diff --git a/pykolab/itip/__init__.py b/pykolab/itip/__init__.py
--- a/pykolab/itip/__init__.py
+++ b/pykolab/itip/__init__.py
@@ -190,13 +190,13 @@
 
         # Scroll forward the kolab event recurrence until we're in the prime
         # spot. We choose to start with the Kolab event because that is likely
-        # the older one.
+        # the older o:wqne.
         if _ee < _is:
             while _ee < _is and _es is not None and kolab_event.is_recurring():
                 log.debug("Attempt to move forward kolab event recurrence from %s closer to %s" % (_ee, _is), level=8)
                 __es = to_dt(kolab_event.get_next_occurence(_es))
 
-                if not __es is None:
+                if __es is not None and not __es == _es:
                     _es = __es
                     _ee = to_dt(kolab_event.get_occurence_end_date(_es))
                 else:
@@ -210,7 +210,7 @@
                 log.debug("Attempt to move forward itip event recurrence from %s closer to %s" % (_ie, _es), level=8)
                 __is = to_dt(itip_event['xml'].get_next_occurence(_is))
 
-                if not __is is None:
+                if __is is not None and not _is == __is:
                     _is = __is
                     _ie = to_dt(itip_event['xml'].get_occurence_end_date(_is))
                 else:
@@ -219,7 +219,12 @@
 
         # Now that we have some events somewhere in the same neighborhood...
         conflict = check_date_conflict(_es, _ee, _is, _ie)
-        log.debug("* Comparing itip at %s/%s with kolab at %s/%s: %r (%d)" % (_is, _ie, _es, _ee, conflict, loop), level=8)
+        log.debug(
+            "* Comparing itip at %s/%s with kolab at %s/%s: conflict - %r (occurence - %d)" % (
+                _is, _ie, _es, _ee, conflict, loop
+            ),
+            level=8
+        )
 
         if not conflict:
             if kolab_event.is_recurring() and itip_event['xml'].is_recurring():