This happens in most bounty campaigns. When I was managing OPUS they did the same thing.
After finalizing the spreadsheet and handed it out to them, they think it's really unreasonable for bounty participants to get equal or even higher amount of tokens than their investors and decided to cut in half the bounty pool. After arguing with the team on slack and having them realize how bad it could get, fortunately they turn back around and gave the full bounty pool as promised.
I think same thing is happening with Bitpaction.
The entire team is just afraid that when the bounty pool is released it will immediately dilute the value of their native tokens since most bounty hunters will just dump them (this is just my theory).
Even though I am managing this campaign, I rarely talk to the man in charge, and later did I know that he also report to someone else (so he's not really on top of the team).
Ever since the team reduced the bounty pool I've been telling @wool_knight aka tab what the consequences this might implicate on their exchange and their reputation, letting them know that the bounty community doesn't take very kindly to this kind of acts. I sure hope this gets solved sooner and a solution to solve this problem benefit all would come up.

PS. Just recently check the spreadsheet and it seems 87.5% of the bounty pool for Signature, Twitter and Facebook campaign categories have been restored.
Tab also said they think this is a fair amount of bounty pool on this campaign categories since the entire bounty campaign ran only for 7 weeks instead of the planned 8 weeks.