Reading node statuses pointlessly initialises first seen millis as last seen millis

      long firstSeenMillis = lastSeenMillis;
      firstSeenMillis = DateTimeHelper.parse(parts[15] + " " + parts[16]);

https://gitweb.torproject.org/onionoo.git/tree/src/main/java/org/torproject/onionoo/docs/NodeStatus.java#n568

Maybe this was done for a reason and later broken, or maybe it was never needed.