Reset ipad to factory settings, restored fr backup in icloud. ipad device password changed to same device PW as iphone. Why?

Ipad 8, 3 years old, running IOS just pre 17.2; a few days ago iMessage stopped working on this device. Apple Support told me to run a backup to iCloud; reset to factory settings; then restore with iCloud with backup. I did. IMessage came back but now the iPad device password changed to the same device password as my iPhone. Why? Is this a problem? My devices have always had their own device passwords.