I've downloaded the MSDS for chloroform from Sigma, and that one doesn't mention avoiding water. Its very strange for chloroform to form hypochlorus acid with water -- what would happen to the rest of the molecule? Would it form methanol? Chloroform can't be that reactive. Likely the information you have (although it claims to come from Dupont) is a typo, meant to apply to another compound, or what happens if chloroform burns. And that is hard enough to in its own right.