yep, mine's turned off too. It's a pain for the wife who now has to manually open/close the liftgate.
I did find some CVN/part numbers for various calibration Not sure if my dealer will know what I'm talkign about though or if these are new or whatever.
Found them here:
https://tis2web.service.gm.com/tis2web/
These a are for Controller K39 Liftgate control Module
Part Number 84100439 - CVN 0000BF4D - Description: New calibration to prevent unwanted liftgate activation.
Part Number 23248777 - CVN 00006CB6 - Description: New calibration to improve Hands Free performance.
Part Number 23171818 - CVN 00007290 - Description: Hands Free Vehicle Access