Apple changed the file format of their new iWork 2013 apps, Numbers 3.0, Keynote 6.0 and Pages 5.0
You can store and sync these files with TeamDrive and open the documents in the file system.
But you cannot open the files in the TeamDrive Explorer and versioning does not work.
You can export the files to a Numbers `09 or equivalent iWork ´09 format and versioning and file opening works fine as before.
We hope this change is a bug from Apple and will be fixed soon.
Previous iWork apps were using the same concept as containers like MS Office Apps (.pptx, .xlsx, ...)
That´s the way syncing causes no problems. The new file format from Apple´s Apps is unreliable as it is not packaged and can not be versioned and controlled well.
And TeamDrive users are not alone with their headache
http://www.macworld.com/article/2059061/dealing-with-pages-file-conversion-and-email-attachment-problems.html