Problem reconstructing Keras's IMDB reviews
Nevermind, it wasn't very clear to me that the defaults for load_data() actually shift the sequence indices by 3, and so to obtain the proper indices for the dictionary you either need to offset those indices during lookup or shift the dictionary values, e.g.:

ind = imdb.get_word_index()
ind = {k:(v+3) for k,v in ind.items()}


And also every review is padded with a 1 at word [0], and so reconstructing the review means starting at [1] or passing start_char=None in load_data()