@DD21 Did you end up finding a solution? I'm using NSPersistentCloudKitContainer to have CloudKit + Core Data and I'm observing the same issue. I have saved ~6000K items in Core Data, which some of them have images. The local size for the sum of the images is around 76 MB, but if you check it on iPhone > Settings > Apple ID > iCloud > Manage Storage, it shows up as ~760 MB, which is the 10x increase in size that you reported a year ago.
This seems to be a bug on the whatever's in charge of calculating the size for iCloud assets, because when I delete my app from my device and let it download all the information stored on iCloud again, it finishes the download extremely fast (I'm assuming because it's only downloading 76MB). If it were downloading 760MB, it would take much longer knowing my network connection speed.
Now, if this bug actually affects user's iCloud quota (which it seems that it does), it is a large scale issue that might be impacting millions of users. Users might have much more iCloud storage space than they think because of this. cc // @eskimo
Topic:
App & System Services
SubTopic:
Core OS
Tags: