I made some on Sunday.. I had almost a cup of oil from the chicken. I know this because no roux was involved. After making the roux and adding trinity and andoille I add the stock with no oil in it to the pot very slowly and allow it to get up to temp with each addition to not break the roux. The oil should NOT separate from the flour.
After that I skim out maybe a couple of tablespoons of oil that came from the andouille.
Only time I have ever seen what you describe is when I was careless and screwed up the gumbo by not having the roux and the stock at near temps and the roux broke up.
This post was edited on 11/15 at 3:15 pm