I am having this issue on Blaze of the Fire Dragon, when you click for the daily sacrifice, it gives you credits and coins as if it works, but when you go back to assistant it still appears to be undone. Also, if you refresh the browser, you can sacrifice for free. Catch being, the credits and coins you got the previous times all disappear.

Also, earlier today I didn't have enough to start a queue in blacksmithing so i sacrificed, then started the upgrade. Hours went by and i refreshed, and it reverted the entire upgrade because it was paid for with coins received through a buggy sacrifice mechanism.

Please fix, this makes it almost impossible for a low power noob to complete the assistant quests.