I keep finding what appears to be duplicate flashcards. Often there is one with -- in front of it, and another without it. For example, 그거 and --그거. In some cases, the English translation is missing for one of them and sometimes the English will be there for both but will be written slightly different, e.g.
안녕 is 'Hi/Hello' and --안녕 is something like 'hi/see you'. Are these just bugs or is there some sort of reason for this?