On 1 Password for for Mac create Login Item "Test"
Attach Document "Test1.txt"
Sync w/ iPad via Dropbox
On Mac, edit "Test" and delete "Test1.txt".
Create New "Test1.txt" with different contents and attach as new attachment.
Sync with iPad via Dropbox
Open item "Test" on iPad
You will see Two attachments, both named "Test1.txt" on the iPad, but only 1 attachment on the Mac.