Found a duplication glitch when using a hammer (any type). After testing I can confirm that it seems to do this with each type of Double compressed block from Extrautils 2, Ex: When I break a double compressed block with a normal hammer instead of getting just 1 block of compressed block or 9 of the lower tier.
pic of amount given: http://puu.sh/t57DT/180ab44392.png

Just did another test. If u try to break a higher compressed block it will also duplicate, however it will take longer to break.

Like @blay09 said, most likely issue with spongeforge or configs