Just curious if it’s just me. 
Whenever I switch from circulars to DPNs I find my stitches get much tighter. (like when I am making a hat and it is too small to leave on the circ) I think it’s subconscious fear of the needles slipping out. It’s not really so tight that you notice the difference, just tight enough to make me grumble and wonder why I can’t loosen up.
If your circs and dpns are different material, it could make them feel tighter.:shrug:
Not sure about circs to DPNs, but I know my tension changes when I knit flat or in the round. Very frustrating, since I don’t want to have to knit all my swatches (cough when I do knit them) in the round.