The fields 'birthday' and 'webpage' are not synced. I can't see these entries in the error log of TB:
sending : <?xml version="1.0"?>
<Sync xmlns="AirSync:">
<Collections>
<Collection>
<SyncKey>{41d4de47-5fdb-445d-adf7-967afa42beca}28</SyncKey>
<CollectionId>c/GroupOfficeContacts</CollectionId>
<Options>
<Conflict>1</Conflict>
<MIMESupport>0</MIMESupport>
</Options>
<Commands>
<Add>
<ClientId>10</ClientId>
<ApplicationData>
<FileAs xmlns="Contacts:">Emil Mustermann</FileAs>
<FirstName xmlns="Contacts:">Emil</FirstName>
<LastName xmlns="Contacts:">Mustermann</LastName>
</ApplicationData>
</Add>
</Commands>
</Collection>
</Collections>
</Sync>