Changing the terms of the bounty campaign in hindsight is unacceptable. From my point of view, the introduction of the mandatory KYC procedure after the end of the campaign is a
SCAM.
5. One week later he change rule and all participants of the bounty campaign have to perform additional work again. But at that time at most of participants work has been already completely performed.
If you've claimed/joined the bounty with predetermined rules/conditions, and you've completed said conditions then you have earned whatever was *promised* at the time. Changing these conditions afterwards is shady at best / an outright scam.