And now i'm looking at some ICO whose website is no longer there and its telegram too, but the bounty manager is still continuing the ICO. Of course bounty manager is wrong, right? Because there is no notice at all that the ICO is a scam
If you feel like a scam ICO is still being advertised, kindly create a topic in Scam Accusations regarding the scam. It may help some members as they invest blindly by looking at these signatures which happened with one of the forum member. aTriz was managing a scam campaign and the member invested in the ICO without investigation and lost his investment. Though aTriz paid half the amount, he has fallen for the Scam.
BM's must check the development now and then and if they feel like it is scam, they must report it in the Scam Accusations board and must end the bounty.
will have an impact on the Bounty Manager who manages ICO?
As mdayonliner said, it won't have a negative impact on BM. But once the ICO is proved as scam and if BM is continuing with the bounty, he must be negged. Most of the trusted and reputed managers close scam bounties if they find them.
Note that, most of the bounty managers are paid weekly for the work they do or as a whole at the beginning of the campaign. Hence they continue their work, unless they are not getting paid.