Twice this week my iphone has not recognised my correct password and I’ve had to restore

As title says, on two occasions this week (on an SE and now new iPhone 13) my iphone has suddenly decided my password is incorrect and locked me out. Got in contact with Apple the first time and they ran me through the restore procedure plugged into macbook but didn’t know why it was happening. Got a new phone today and same thing happened again after password was working previously.

Originally had iphone 12 but smashed it so was using spare SE when issue first occurred. Got new iPhone 13 today and everything was fine until just now when phone has suddenly decided my password is wrong again. I’ll literally be using phone as normal with normal passcode and then all of a sudden passcode stops working and I get locked out.

Does anyone know why this is happening?