@j91z28d1 is right on; the calculated alcohol content (by what's known as a virtual sensor) is what is causing the PCM to dump fuel into the system; your Autel should have a function to reset the fuel alcohol content and that will restart the % calculation. Resetting that may also reset the LTFTs.
Again, there was an issue with some of these with the PCM mis-calculating alcohol content, and an updated calibration was made available by GM. If you have a shop that can update modules (GM dealers can, and some shops can) you may want to take it in and have it checked to see if an updated calibration is available.