(I'm not sure if this is the right component to assign specification bugs to, but there is no separate component for them.)

Section 6.2.1, floor header decode, says:

7) if any of [floor0_order], [floor0_rate], [floor0_bark_map_size], [floor0_amplitude_bits],
     [floor0_amplitude_offset] or [floor0_number_of_books] are less than zero, the stream is not decodable

This is not meaningful; all the variables listed above are indicated in the previous lines to be read as unsigned values from the stream, so they couldn't possibly be less than 0.