Worth to mention, vadoff was active last time on July 04, 2018, 12:28:09 PM while bounty started on August 25, 2018, 05:09:11 PM.
Maybe someone used your telegram and vafoff's forum account? I've seen this many times in telegram bounties.
Yes. I agree with this. I have experienced several times and those are just the tricks of cheaters. Sometimes, they use bitcointalk username of active members with random telegram username in bounty group to join this bounty campaign, even no longer active bitcointalk accounts with fake telegram usernames. It seems work with some campaigns due to negligence of bounty managers.