I discovered today that an attachment that I deleted on the Mac beta yesterday still exists on two iOS devices. There is no capacity in the iOS version to delete attachments, or add them for that matter. I'm posting this here because it strikes me that it might be the same general issue as described above.
In earlier betas there was a problem with deleting attachments. Then, deleting one in OS X would remove the information from iOS on syncing, but it would leave an empty entry for the old attachment. In this case, the entire attachment persists, not just the empty record of its past existence.
I should add that I use Dropbox for syncing. My Mac version is 4.3.1.BETA-7. For iOS it's 4.5.1.
Back to report that I can manually rid myself of the unwanted attachment by duplicating the record on the Mac. The duplicate obviously doesn't have the attachment, and when it syncs to iOS, the attachment is also gone. Inelegant, to say the least, but it's the same work around that we had to use when the attachment left a blank stub in iOS after deletion from the OS X version.
I've split your other posts into this iOS beta forum because that's a still known bug in the iOS app (we haven't fix it in 4.5 either) where the attachments are not properly removed after the sync.
We plan to fix this relatively soon as we continue to polish up the overhaul and focus on the attachments next.