Good notes and information, you forgot to mention if it was a left hand or right hand brisket. We all know the left hand ones are more tender.
I'm not familiar with the flow dynamics of a Treager, but I'm guessing the heat flows across the top of the grate and that's why you went with the fat up?
And with those temps (both pit and internal) you should have been close, but you have to cook a brisket tender and not really count on the internal temp. So maybe it was not done enough. It's hard to explain but in foil, things reach a temp but it takes time for that temp to soak-in and work in your favor. Maybe you caught it as soon as it got to the 200°, or maybe your thermometer was off a hair.
As far as toughness goes, with no disrespect, did you slice it against the grain?
KCBS - CBJ
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