[horde] Activesync Calendar not in sync

[Philipp Fäustlin]

Since Horde 5.1.2 (Horde_ActiveSync 2.7.3) I have a problem syncing with 
activesync.

After the initial sync Calendar entries/changes in Horde won't get 
recognized and won't get synced to my devices.

Changes on my devices (IPAD, Outlook 2013) instead are immediately 
synced to Horde calendar.

Changes in the horde calendar don't even show any changes to activesync 
log idling.
----------------------------------------------
2013-09-12T17:53:49+02:00 INFO: [27538] SyncCache collections refreshed.
2013-09-12T17:53:49+02:00 INFO: [27538] Refreshing @Calendar@ from the 
cache.
2013-09-12T17:53:49+02:00 INFO: [27538] Initializing state for 
collection: @Calendar@, synckey: {5231d4ef-1a64-475c-9e98-75d29029041b}6
2013-09-12T17:53:49+02:00 INFO: [27538] Loading state for synckey 
{5231d4ef-1a64-475c-9e98-75d29029041b}6
2013-09-12T17:53:49+02:00 INFO: [27538] Initializing message diff engine 
for @Calendar@ (@Calendar@)
2013-09-12T17:53:49+02:00 INFO: [27538] Using MODSEQ 962060 for @Calendar at .
2013-09-12T17:53:49+02:00 INFO: [27538] 
Horde_Core_ActiveSync_Driver::getServerChanges(@Calendar@, 962060, 
962060, 1376582029, 1)
2013-09-12T17:53:49+02:00 INFO: [27538] Fetching changes for calendar 
using MODSEQ.
2013-09-12T17:53:49+02:00 INFO: [27538] Found 0 message changes in 
@Calendar at .
2013-09-12T17:53:49+02:00 INFO: [27538] Sleeping for 5 seconds.
--------------------------------------------

Is there a bug or do I have a configuration problem?

Regards

Philipp Fäustlin