That is really bizarre. You didn't happen to add any other ingredients to your distilled water such as honey or milk did you? Adding those to your lye water can make it turn color, but if it was just lye and water, it should have turned cloudy-white and then back to clear when the lye was all dissolved.
Hmmmm...Where did you get your lye and what brand is it, and what did the actual lye look like before you poured it?
Does it say anywhere on the bottle "100% sodium hydroxide", or "100% caustic soda"? If not, then I'm guessing that your lye has other stuff in it, possibly for use as a drain cleaner? I personally would be afraid to use the soap, especially if I couldn't put a logical finger on why it turned brown.
IrishLass