The Facebook events sync is buggy on some phones (HTC 2.2 ROM for example).
This problem have been discussed multiple time on forums, and it seems there is no solution to fix this internal sync.
A solution is to export your Facebook events as an iCal.
This is how I solved it on mine:
- Go to FB, click Events on the left, click “Export Events” on the bottom. Copy the link it gives you.
- Go to your Google calendar, on the left under “Other calendars” click “Add”, and select “Add by URL”.
- Paste the link from FB and click the “Add to calendar” buttom
- You’ll see your newly added calendar on the left, hit the dropdown arrow, and click “Calendar settings”.
- Rename the calendar to “Facebook” or whatever you want and click the
- Click the dropdown next to the Facebook calendar again, and select a color you like (I use blue).
- That’s it! Google will stay in sync with Facebook, and your phone will stay in sync with Google. It all happens virtually instantly – even better than the BB!