Yes to background data. Yes to auto sync. But it shouldn't matter. It doesn't work even when I sync manually.
Right, I understand that, I just thought I would ask to get an idea of what you're working with. The more you know, yada yada.
Some people say that clearing the Calendar's Application Data can help resolve this issue:
Calendar won't sync with Droid - Google Mobile Help
1. Press your device's < Home > button, then press < Menu >.
2. Select Settings and then Applications.
3. Select Manage applications.
4. Press < Menu >, the select "Filter."
5. Select "All."
6. Select Calendar Storage.
7. Press "Clear data."
8. Wait for everything to re-sync.
Give that a go and maybe it will help fix the issue. Several people on that thread said it worked for them. I just did this to see if it would resync, etc and it sure did remove the data on the phone and resync with the online calendar.
Maybe you have some bad data some where? It's worth a shot. :icon_eek: