When Bitcoin began to decline from $5,000, the entire surrounding market was seriously affected. A large number of miners went bankrupt, and the bounty task is now facing challenges, so I think this is caused by the market downturn.
in fact the effect of the market downturn affected the course of the ico project which held a bounty campaign. when many ico fail and don't get development funds, the bounty won't get anything. it is a risk that has been accepted by bounty hunters in participating in the campaign.