That's a tough one dude. If I had to guess, it sounds like some weird data corruption issue. FYI, I'm a programmer who deals with weird data corruption problems all the time, so I'm not just making stuff up.
Unfortunately, about all I can do is tell you what I'd do to try to figure it out. From your post, I assume that it syncs correctly with your iPhone. I assume that you where using this: Google Mobile | Sync for your iPhone If so, Google Mobile Sync uses the Microsoft ActiveSync protocol ..... so I would guess other ActiveSync based solution would sync fine too. (more on this later)
I don't know what protocols Synergy uses with Google Contacts, but I don't think that it is Activesync ... since it pulls in ALL contacts ... and not just "My Contacts." My hunch is that there is probably some weird character or something in one of your contacts that is screwing everything up. I would guess that it is the contact that steals half of your other contacts numbers and email addresses.
On the day the Pre launched, I wrote up a tutorial on using NuevaSync (free service) to sync my Pre with Google. That product is based on ActiveSync, too. More than like it would successfully for you. You can search this forum for NuevaSync and find it. Or you can go read it on my website: Palm Pre: Only Sync Google “My Contacts”
Aside from the Nuevasync stuff, this is what I would do based on these assumptions/guesses. I'm putting a lot of extra steps in hear in efforts to minimize the likelihood of messing something up with your account.
Copy all of your contacts to a new google account for testing purposes only
- Go to your Google Contacts ... http://www.google.com/contacts/
- Click export and choose the Google CSV option. Save the file to your computer desktop and name it something that you can remember.
- Create a new Google Account and import your saved CSV into contacts on the new account
Ok, now you have something to test with against without worrying about messing your contacts up.
- Setup your Pre with your new Google Account. I'm expecting you'll get the same results.
- Go to the Google Contacts website and delete the contact that takes over everyone phone/email.
- Resync new Google Account with Palm Pre
Do all of that and post back with your findings. I'm going to subscribe to this thread so I'll be notified when you post.