Hi Andre,
One possible cause of this not-appeared on Google trouble which have come to my mind is "Last Sync Date Time". Please initialize Last Sync Date Time by selecting action from action bar of GooCalSync db, [Action] -> [Initialize LastSyncDateTime]. This action set Last Sync Date Time to be 1900-01-01. So every calendar entries on both side which is newer than 1900-01-01 are examined whether or not to be synched.
Please try it and let me know the result.
Thanks in advance.
Muneyuki.