Okay, I learn something new every day....I found this keychain support link that might help.

It is a setting on your Mac running Mavericks: System Preferences --> iCloud --> Keychain option. Mine is not checked because I do NOT use the keychain, which I think is a PW memory feature.

I set the username and PW for Safari bookmarked pages directly in Safari, so that would explain why I'm not having the issue, assuming it is an iCloud syncing issue.