If you tell us more about your cook and procedure you might get some help. From the pix I would just about bet your cooking to a Temp. Cut the wire off that farkin meat probe. When that probes slides in like a hot knife cutting soft butter it's done! The bark looks dry I noticed in the first pic that the brisket is almost void of a Fat Cap ( was it pre-trimed or sometimes called Super trim?) and the big chunk of hard fat was left on (left side of pic) that should be removed before cooking.
Try and get an untrimmed brisket remove the Big chunk of fat and thin the Cap to 1/4" as it renders it will bast the brisket keeping it moist and will turn into the "SugarCookie"
How to trim a brisket
Hard fat removed, Silver skin and fat cleaned up on under side of Flat
What was trimmed off
All cleaned up ready for the rub fat cap down Point to the left
On the pit, notice no probe in the brisket