I work with bounty more than 2 years and it seems period of paid more longer that be in 2016.
Lately, many bounties that hold payments are not like last year, at least we have to wait 3 months for payment and sometimes the results we get are not in accordance with the length of the project we are doing. Sometimes there are successful projects but are refuse to pay by saying bounty hunters do not help boost marketing, all done by the team or for blogs are all just copying from the whitepaper.
So it depends on the project. In the past there is one group paid 2 weeks after ico was finished but now it's 2 months after ico.