So I take it that you bring water to work for the plant since you say you use the same water on both plants? The yellow is often from using floridated water but I have had mine start to yellow when the seasons change and the amount of light it gets changes. I have to move mine around. Maybe try a new spot for it? I don't know how sensitive they are could it be somethng as simple as different room temps between your home and office? Also it has been proven that plants are sensitive and react to electromagnet fields (look it up) and it could be the office equiptment near it.

Also consider that maybe some "helpful" do-gooder has been watering your plant at the office with tap water. I had a roommate once who killed my Dizygotheca elegantissima (Finger Aralia) by overwatering it even, though she was constantly told to stop water my plants and even specifically told not to water the Finger Aralia. The browner it became, the more water she dumped on it, she did not get it. Some people are both stupid and stubborn. Consider too that maybe some officemate carelessly dumped the remnants of their coffee or energy drink in it, or even purposly tried to kill your lucky bamboo out of jealousy.

try puting it in a hotter spot