It's working fine today. Weird, because I did maybe 10-20 or so and they all did the same thing, even after refreshing the screen. The thing was that because it changed the text e.g. "il sedano" because "ilsedano", it wouldn't find the original to match. But it works now.
The duplicate thing is not a big issue. I just added a word yesterday and accidentally hit enter before I'd typed the meaning, so now there's an empty word in the list. You said "When you click on the highlighted word or phrase you can still add information on the Notes without having to go to the Vocab list" but that's not right. I think you used to be able to do that but when you now hit save, it tries to add a new entry and so fails with a message of:
Whoops! Something went wrong.
Vocab already exists.
But, honestly, if people want to get more points quickly that doesn't make a lot of sense. I use the points to try to make sure I make a reasonably consistent effort every day and it does really make me try to make sure I keep the points up as a measure of the effort. If I were to cheat that, that wouldn't make me learn the language any quicker!