Bukkit

What steps will reproduce the problem?
1. Use gold as currency (nugget: 1, ingot: 9, block: 810
2. Set max balance to 10,368 (128 gold blocks)
3. Put in more gold than you are allowed to have

What is the expected output? What do you see instead?
I would expect the ATM to not accept the gold, and put it back in your inventory.
However, instead, the gold disappears, and the balance either increases, or caps at 10368.
Sometimes the balance increases and until you pay someone, it won't realize it is too large.
Then if you have, say, 20,000 gold and pay someone a dollar, it goes back to the max, 10368.
But the physical gold you had in excess is all gone.

What version of the product are you using?
version 1.8

Do you have an error log of what happened?
No I do not.

Please provide any additional information below.