ICal (Client) version with 10.6.2, intermittently loses "Refresh Frequency"

Question

iCal (Client) version with 10.6.2, intermittently loses "Refresh Frequency"
10.6.2 SLS with 1.5 mo. new MacPro tower with 4 Cores (just bought)
3GB RAM
Network Homes
Network Calendars (only, no published things, no busysync, all Apple Champagne)
iCal Server enable
Solid, fast network homes, logins quick, kick-*** OD implementation, very few beach balls, though they grow when I get all 12 delegates refreshing calendars every minute.
Push turned off (it doesn't work as advertised, in my tests)
Set iCal client to refresh each minute
12 Read/Write Delegates for each of 13 workstations. (so, we're really expecting a lot, but not a lot, like in, we expect Exchange/Outlook robustness -- on open standards woo hoo)
But yeah, the main symptom is that the ical client loses it mind (at some as yet undetermined interval) and stops refreshing. And the formerly trusting Calendar user, misses a meeting, because the change the delegate made to their calender didn't refresh and the Calendar user shows up an hour late, or misses the event entirely. That won't work.
OK. back to what I've tried. (I haven't tried, but am considering it, moving to PHD)
I have turned off PUSH. I hope that returns some server processing cycles.
I have ( and this fixes it temporarily ) set their refresh frequency to manual. Close Prefs. Open Prefs, set back to 1 Minute. Close prefs. And that holds for a day (?) two days (?) I haven't gotten that far yet. I did that last night. And it saved me from having to remove and add the network calendar account. So, my remedy is down to about 40 seconds and 10 mouse clicks. Still annoying, and should work properly.
Apple Enterprise support is being awesome. They send me the engineering capture tool and I am awaiting the symptom return. Then I run that app and it gobbles up lots of logs on an affected client workstation and the server. So, wish me luck, and send any thoughts or ideas along.

Answer 1

This looks like a bug in the iCal client. I, too, have had problems with delegated calendars and end users mistaking events for being missing, not updated or incorrect only because their local copy was not synced with the true copy on the server. The refresh rate on delegated calendars can be changed with the "Refresh calendars: [ Every 1 minute ]" preference. You can verify this by right-clicking or control-clicking on the delegated calendar and choosing "Show CalDAV Queue." This brings up a queue of activity with the iCal Server. You'll note at the top that it mentions "Refresh every 1 minute."
The problem, of course, is if you quit iCal and recheck the "Show CalDAV Queue" on the delegated calendar, the refresh interval has reverted to some long interval like 300 or 900 minutes. This is a bug, for sure. For now, you can tell your clients not to quit iCal or to refresh manually or reset the refresh interval whenever they restart iCal/their computer, etc.