IPhones sharing neither Apple ID nor iCloud somehow still sharing data

Question

My girlfriend has recently acquired her sisters old iPhone 5s running latest iOS version as of writing.

Her mother has an IPhone 5s as well, under similar conditions.

Both devices are linked to distinct iCloud and Apple IDs.

My girlfriend's phone contains a number of contacts belonging to her mother. When she deletes one, it is removed from her mother's phone as well.

How do we prevent this?

Answer 1

This happened to me I gave my husband my old apple 5s but didn't wipe it clean first. He deleted 3-400 of my contacts in a 1 hour period since they were still using the same iCloud account. From experience I now know to rest the old phone to factory default and set it up that users own Apple ID. Problem solved except couldn't recover my contacts since a new update was being performed and didn't have a current backup.

Answer 2

Contacts can pull information from multiple locations:

• The device has a local store
• Connecting the device over USB to a computer can put contacts into this local store
• Many cloud services will sync contacts - look here since you are seeing a deletion propagate off one device and on to another.

Open the settings app.

• Mail, Contacts, Calendars
• Delete each account that has contact syncing for an account you don't want on that specific phone

You can choose to delete all those contacts when you turn off each sync service or retain the contacts locally and then clean things up as desired.