understanding difficulty

[pineapples]

hi,
newbie to mining here, not really doing it for profit but fun

but i noticed when mining catcoin using a CPUminer and CUDAminer, i got two different difficulties.
how does that work ?
cpu was 16, and cuda was 8


right now, i think a new block was just found.
and i'm geting CPU 8khs with 2.39 difficulty
CUDA 5 khs with 2 difficulty.

[Hypnoise]

seems like mistake made by miners, network diff cant be different