I am not sure if I can help you, but I am also precipitating portiens using a different method, Ammonium Sulphate... But what I have experienced was that cloudy occurence when washing out the salt. Apparently I forgot to test the average pH of the Protein extract that was redissolved in a buffer. when I added the wash, it was of a lower pH wich gave the cloudy solution, then I had increased it to neutral n not happened, which was suppose to be.
I don't know if this might be the problem when one was cloudy n the other not, remember proteins have different pI values!