I have a very quick question regarding causality and coherence. I have two plots- one showing causality from node-1 to node-2 and other showing coherence between the two- both vs. frequency.

What I am getting is: a DIP at the same frequency in coherence plot where as a peak in causality plot at the same frequency. To be brief-

1). More the causality (from node-1 to 2) at a particular frequency, less is the coherence between the two.

2). Very less causality when coherence is high.

Is it very common or it should not be like that ?

I would greatly appreciate any kind of idea/suggestions.

Thank you.

MJ