i have always had this issue with spring IKs. I guess its a glitch, what do you think? I tried connecting the rotation y of the globalMove to the twist of the IK..

edit: so i actually got this to work on one leg, but the trick isn't consistent with the rest of the legs even in other rotations. If you've ever found a solution to this let me know. 

It's actually a very old issue. Group the IK joint chains separetely from your hierarchy and parent constrain them to the bones they should be otherwise parented and scale constrain that group to the master controler. In some cases you might see some poping when rotating the master but if you move the leg controls slightly they pop back in place (think it's the constrain not evaluating in time). Hope that helps.