Note: This question is different from "How does the bounty system work?" in that it does not ask if a bounty can't be corrected, but why.
In the following question
How to load foreign image via POST request in browser?
I wanted to award the accepted answer with a bounty. I received the question whether I was sure, and hit "cancel". I reassured that I really wanted to assign the bounty, repeated the step and hit "ok" on that confirmation.
To my big surprise, the bounty wasn't awarded to answer at hand, but to one answer lower.
So the wrong answer received the bounty.
Not sure whether this is really a bug, or whether this was my fault. Since I can't undo, and repetition costs lots of time and reputation, it is impossible for me to debug this any further.
In general, isn't it a bit risky to make bounty assignment not undoable?
Shouldn't we allow for undo for about 1-5 minutes after awarding the bounty, the same way we do for questions and answers?
That would have lots of benefits, as described above. What are the reasons to go along a different route and making this a one-shot permanent action?