If Tapas has a way of identifying bots, fair enough. And it could be that they were skipped over because Tapas just didn't care for the style or subject matter.
But Lucille's author did have followings on multiple social media sites, so if that influx of subs were legit from fans and friends, I don't see why they should be considered cheating. An author's ability to drawn in NEW readers to the site is exactly what Tapas wants from premium content. And I don't know about Dark Silence's author but I did see them get a shout out from another creator with over 2k subs, which would definitely explain any boost they got. Nothing but respect for the winners, but I do feel bad for these guys.
But that's the nature of a contest based on subs. If the system is that easily exploitable (or even if Tapas is inclined to believe it is) better they just do judge's picks from now on.