Re: InuYasha - The Final Act: Boxset 1 (Blu-ray)
To be fair, 13 episodes could technically be considered a "season".
If you're going by seasonal airings in Japan, but even then it's not always the case and/or doesn't really even work. Not to mention Japan never really seems to have any set consistency with "seasons" for their ongoing shows in the first place, instead just opting to split it by certain arcs.
tl;dr anime seasons are weird ass shit