Yesterday I noticed that my Keychain passwords had been deleted - I wonder if it’s related? First, some of the passwords on my iPhone disappeared. In response, I decided to switch on Keychain for the first time on my new M1 MBP to see if that would solve the problem. However, now all my previous Keychain passwords on my iPhone (nearly 30-40 of them) have been deleted and replaced with about 10 passwords I’ve created using my new MBP. Has this happened to anyone else? I’m going to try and get in touch with Apple support tomorrow.