2016 sierra slt park assist won't stay off

[chasin tails]

Hi Newbie here, patience please. I have a 2016 Sierra SLT crew cab SLT. When I go into settings to turn off park assist, its does turn off, but when I turn off key or engine and restart the assist comes back on. I called my gmc and they said I was turning it off correctly and should contact the dealer. Any suggestions.
I tried with engine running and key in on/run position with same results.