Saved a Gumbo with separating Roux

I've read about Roux separating but I've never actually seen it. My wife makes a pretty mean gumbo and I usually have the job of stirring the Roux until it is the right color. As I'm stirring the Roux watching it turn into a reddish chocolate milk color. I did think the Roux looked a little oily but not too far outside of the norm. My wife is pretty detailed about measuring stuff out so I don't think anything of it. Roux is done I go away untill the wife calls me in the kitchen.

"What is this sludge floating on top of the gumbo?"

It is something I've only read about in internet lore... The Roux had separated. Did some googling and most people say to jack up the heat and stir. I turn the burner up to 11 and stir. Roux isn't incorporating. Wife is ready to throw it out There is a whole chicken, 2lbs of sausage, and several hours of time invested in that pot I wasn't ready to give up yet.

I break out a small pot and scoop out all of the unincorporated sludge off the top. I make a corn starch and water slurry and add it to the gumbo pot to get a little thickening action starting. Then I turn on high heat on the small pot. I use an immersion blender as I bring this mixture to a boil. I keep heating and blending until everything looks incorporated then I add more stock from the gumbo pot. I heat and blend some more and turn it off and let it sit to see of it separates. It doesn't so I throw the whole thing back in the gumbo pot and there is no more separating. The gumbo was saved.

These were my observations from saving my gumbo.

1. I wouldn't turn the heat up and stir the main gumbo pot. This process started breaking down my chicken chunks I had on my gumbo and made for overly shredded strings of chicken.
2. Removing the separated roux and heating and stirring in a separate pot with the immersion blender worked great without over stirring and breaking down the cooked contents of the main gumbo pot. By adding stock and mixing in the small pot I could check to see if the Roux was still separating before I added it to the main pot.
3. I don't know of the corn starch did anything. I was originally in panic mode and was just removing the Roux and was going to see what the gumbo tasted like thickened with corn starch missing most of the Roux. I used about 3 or 4 slightly bulging tablespoons to make a slurry which I added to an 8 quart stock pot. It was just enough the contents started to look like it was thickening but not enough to where the finished product should have been. Did the corn starch help jump start the Roux incorporating or is it a placebo effect? It was encouraging seeing your pot of gumbo start to thicken after the Roux has separated even it it isn't the Roux doing the thickening.
4 I couldn't get 100% of the separated roux out. It just sort of disappeared on its own. Once I ladled over rice you couldn't see or taste it.