There seems to be a problem with adding flashcards from dictionary entries that have the same characters, but are different in pronunciation - if that difference only is that the second entry has fifth tone where the first entry has an actual tone.
Example: According to both Guifan and PLC, 本事 ben3shi4 and 本事 ben3shi5 do mean rather different things. If I add the first to my flashcards and then try to add the second, I get informed that the second entry already exists in the flashcard database - although this is not really the case.
I see how this might be useful in certain cases, but I think it would be even more useful to be informed what actual entries are regarded as being duplicates of the card I am trying to add. E.g. something like "You've already created a flashcard for 本事 ben3shi5 / skill, ability" rather than "You've already created a flashcard for this word".