This is how I fixed it. After the C1 re-learn it was 100% better. Decided to do the C4 learn too to be 100% sure. Took about 30 minutes early one saturday morning when there was no traffic.
https://gm.oemdtc.com/6777/16-na-019-information-on-transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-slips-or-flares-2016-2017-buick-cadillac-chevrolet-gmc
To Learn C1 (For 6-7 or 3-1 Shift)
Pressure Learns:
Note: It is recommended to utilize a road with a speed limit between of 30-45 mph (48-72 km/h) for this procedure.
Shift the transmission into 6th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1600 engine rpm. Maintain this condition for a total of about 5 miles (8 km). Cruise control may be used and has been found to result in faster learning of the clutch values.
Volume Learns:
Complete 15 light throttle 6-7 upshifts at approximately 15% throttle to further learn C1.
I also did this:
To Learn C4 (For 1-2, 5-6, or 7-8 Shift)
Pressure Learns:
Note: It is recommended to utilize a road with a speed limit between of 40-45 mph (64-72 km/h) for this procedure.
Shift the transmission into 7th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1750 rpm. Maintain this condition for a total of about 5 miles (8 km). Cruise control may be used and has been found to result in faster learning of the clutch values.
Important: Application Specific Express & Savana Vans Pressure Learns:Perform 10 normal mode 7-6 coast down shifts (zero/light brake) to learn the C4 Return Spring.
Volume Learns:
Complete 15 light throttle 1-2 upshifts at approximately 15% throttle to further learn C4.