re: Please help me figure out how my roux separated! (with pics)

It has happened to me a few times as well. You will not find an answer as no one seems to really know. I think the scientific method is needed here.

My theory is because the roux is too dark (ie burned). You and I may not think it's burned (that's the color I shoot for), but every time I've had this problem was when I made a really dark roux. I bet you wouldn't have the problem if you stopped at peanut butter stage.
.....Just my theory