We have experienced issues with the modification of shared calendars with the iSync connector. The shared calendar is created using the ZCS web interface, and shared to the recipient. The recipient then logs into the ZCS webpage and accepts the share. The calendar appears in iCal after the next sync.

The problem exists after an event has been modified more than once. Here are the steps we performed to replicate the problem:

1) User1: Create an event in iCal

2) User2: Modify the event

3) User1: Modify the event again

This causes an error. The expected behavior is to allow the event to be modified as many times as necessary with no errors.
Modification within the web interface is fine.

ZCS Version: 5.0.11_GA_2695.RHEL4_64_20081117020633 RHEL4_64 NETWORK edition
iSync Connector: 5.0.2672

iCal Version: 3.0.5 (1270)
OS X Version: 10.5.5

Please let me know if there are any settings that require modification.