Yes sorry i did remove it. I have since added it back to the production site stated above.
I get that -0.31em; is the size of the area in question. I just tried a larger number to see if I could see any visible change to the reduction in size of the area between the items.
Either way I loose the 0 from the -0.31em; portion of the CSS after saving the stylesheet. Maybe its a bug in the Jetpack CSS editor?