I also have had similar things happen with Identity Safe, but not often. When it's time to change my password at my banking site, after I'm fully logged in, I have to temporarily disable the login feature before continuing with my password change. If I don't, an extra field gets filled in when I click submit. Then my entry is rejected by the banking site. You can't copy/paste, they're on to that. At my banking site, you have to type your current password, then your new one twice, I'm sure like at most banks. At my bank there's a 4th field that stays empty. If I don't temporarily disable the login feature, the 4th field will be filled with anything available from the Identity Card.
So I have become use to this and don't find it a major concern. Otherwise all of the other many sites I visit using Identity Safe, including Norton Community, the feature works flawless