When you use the lens of color, you can make lapis lazuli from dye, which is a lot more EMC (mass/energy used by ProjectE. All items have their own) than any dye, you can effectively loop this to gain more and more EMC.

The procedure of the exploit:
1: Put any dye. EMC is 16 by default
2: Change it with the lens until you get lapis lazuli
3: Convert lapis lazuli into a lot of dye
4: Repeat.

How to fix:
Add "blue dye" that replaces lapis lazuli.

No point in trying to balance around PE