I have removed the bounty and rolled back the edit. In the future, if this comes up again, feel free to raise a custom moderator flag, since moderators have the ability to remove a bounty, refunding the reputation spent.
Each time you add a new bounty to the same question, the minimum amount of reputation that you can offer is doubled. From the Help Center:
Additionally, if you offer multiple bounties on the same question, the minimum spend doubles with each subsequent bounty (50 reputation on the first bounty, 100 reputation on the second, 200 on the third, and so on).