That sounds exactly like a failed spring. It only needs one to work, but the second one gives the snappiness in the shift. Note also that is it VERY easy to set the gear outer so that it is not 100% snug against the stop in the ergo body before you tape it into place and wrap the bar tape. The only symptom is that it's all a bit mushy. Also some fancy cable end stops don't sit happily inside the ergos. (Been there, done that!)
The best way to get it right is to cable it all up, set it onto bottom gear, then have a good tug onto the exposed inner to set all the outers into their stops, Finally tape the outers onto the bars with a couple of bits of insulating tape...then wrap.