Contacts Sync

I have a very strange issue which requires a little back-story. About 4 years ago, I lost my phone. Unfortunately, I did not have my contacts in iCloud. I got a new phone and slowly got back the contacts that I needed. Today, we erased and set up as new an old iPad that we have. Somehow, it synced the contacts from my old phone into the contacts app on the iPad. I am utterly perplexed. Since my wife didn't want all old contacts on the iPad, I was able to go into "Groups" and uncheck my name - which fixed the issue - but I am utterly confused as to where the iPad found these contacts as, again, they were not in iCloud and the contacts that it does find for me do not match my current contact list (which is in iCloud). Anyone have any idea how this happened?