I was having difficulties and error on my previous Google Drive on my iPad. But now it seems Google already fix this sync problems. After the new Google Drive 3.4.1 released, the sync problem on iPad are fixed. Now my iPad can sync and get the most updated files and folders on my Google Drive accounts. I have three accounts through my iPad and all works pretty well.
If you have sync problem on Google Drive on iPad or iPhone. Make sure you update your Google Drive to version 3.4.1