For how long are going to wait for the Altcoin season to come?, no one knows. And presently, promoting bounty projects at this era seems to be a waste of time to me. So the fact still remains that the best time to promote bounty projects is during the bull run.
You can not know in advance when is the best time to promote projects. you just have to do it always if you want to make money.
Bounty hunters will continue to collect tokens from many projects and in my opinion all the time is good to promote it if in the end you receive payment. Altcoins season will no one know when it will come, so by continuing to hold the tokens obtained during the bearish period I think that is also a very good effort, because when the bull happens sometime later the bounty hunter will get good results too. So there will be nothing useless for the efforts that have been made all the time.