How did office hours between the two batches go? That was left out of the blog post.
Similar to when you're in the lunch round during a job interview are told "oh don't worry, lunch is not an interview, just relax", I imagine attending office hours after you got rejected last time is in the same boat - it's another hidden interview. It's possible that there were indicators during that time period that indicated how the next batch might go for you guys :/.
Best of luck regardless