I recently had a situation where I did melodic using 'dswau' files from conn, selecting networks that spatially correlated with the Yeo networks. To my surprise and my co-authors surprise, there were no anticorrelations between any of the networks. I'm now running a new project looking at task-based fMRI, and seeing the same thing, but using ROIs from CEN, DMN, SN, instead of ICs. I've attached connectivity plots (fisherz transformed) , as well as a couple example QCs. I'm doing filtering and despiking outside CONN for the new project, but I did it together in the first one - so I don't think that's the root of the findings. 

The one instance I got anticorrelations was when I ran GIFT on 'dswau' files, and the anterior DMN component was anticorrelated with other networks.