Hello Steemians!
Have you also noticed the bonus STEEM in your author rewards from this past few days? I noticed it too, but I think it's still in an on going process, since it last only for a few days and I haven't already received my bonus STEEM author reward within this past few hours. Maybe, it's because the Steemit team are just doing a dry run about it, and they are planning to add that in the system very soon, or it's not fully functional at this moment, so they are trying to quickly work on it.
Despite of that bonus STEEM rewards, I also have some confusion about the Steemit's reward system. I joined here in Steemit, last December 2017 and I'm still not aware about the author's reward system. I have no idea on how the Steemit's system compute the Steem Power author rewards, since we are allowed to choose on what type of reward we want to receive, we can choose from either Power up 100%, Default 50%/50% or Decline payout. The default 50%/50% doesn't seems to have the right computation, the ratio of SP and SBD rewards isn't proportional. Maybe, it's because the system are just trying to balance the rewards system, to prevent an exploits or excessive rewards from using bid bots, since we can still have a profit or some few losses in those bid bots, at this current reward system, while increasing the Steem Power reward will going give us a too much excessive reward.