It depends on the rules and plan of the whole bounty program. That is the more reason why you are required to read thoroughly and understand the rules of the bounty program before you attempt to do it. It becomes normal to wait for six months for bounty payment when it was stated in the bounty program but abnormal when the otherwise happens.
This is clearly not normal if the bounty manager hadn't mentioned during the bounty program that the payment will be after 6 months. You got two scenarios here -
(i) Some weak projects come up with an idea of locking the bounty and airdrop tokens to avoid big market dumps after listing of the coin/token in an exchange. This is done for the benefit of the early investors and the team in mind.
or
(ii) Wantonly delaying the distribution process so as to avoid the payment. So most probably the project is trash or scam.
If its the first case, then you might get atleast something for the work you have done. If its the second case, don't even bother to receive the payment. But in both cases, it's not a good sign of a good project.