Double Imported Books from Calibre

i got an issues, when importing from calibre, i've got duplicated books (one with same format, the others with differents formats)e.g : Book A and B from Calibre -> imported to Bookshelves -> Three Book A (pdf, epub, epub), Two Book B (epub, epub)note : when checking the calibre library folder i found two diferent version of the ebooks, but i do think you should consider this to be merge when imported.