The issue is with act 3 and 4 sharing the same town map and tyrael. So if you complete both act 3 and 4, the turn in order may mess up and tyrael may complete the non-bonus act first before the bonus causing the "bug" leading to 1 less cache.
To be safe, leave 1 bounty incomplete for each act 3 and 4 and wait for their bonus turn accordingly before completing that last bounty.
Rest of act 1, 2 and 5 don't matter as long as you only turn in as per bonus order.