One of the contacts in my galaxy s3 shows a small "hd" next to her name for incoming phone calls. When this person, who also has a galaxy s3 (not linked or connected to my phone that I know of), calls or texts someone, the caller id on the receiver's phone looks like the call is coming from my phone, not hers. It's not clear whether this is happening with everyone she calls or just some people. This is so wierd I don't even know if the question makes sense. Can anyone help?
This seems to be a known fault with Samsung devices. See the link below on the Android issue tracker (initial report dates back to January 2015). It seems to be a Samsung issue, not necessarily just your device, and not an Android issue.