Owners/service Manual problems of the 2018 Buick Enclave

Premium package comes with safety alerts. However three of the alerts do not provide any of the safety function described. Front collision alert - have had three emergency braking situations and in all three where the red beeping alert in the dash did not function. Tested by gm engineer and he could not make it work at over 20 mph. Icons in instrumention light up so it is seeing cars but no warning at stated. Front pedestrian alert - similar to above, car is seeing pedestrian because icons light up green and amber but flashing red and beeping do not occur when you get in danger zone lane departure warning - there is not beeping when you cross a lane without using turn signal. Land adjustment works so vehicle is seeing lines but if you cross the line without any manual effort the alert does not work a gm engineer for the houston area drove the car and could not get any of these functions to work. He called gm and was told not to test this the front collision in the field but that it was tested at factory and worked as designed. So gm says there is not issue even though I have had 4 situations where it should have worked and the gm engineer could not get any of them to work as other gm cars. Other Enclaves on the lot all have the same issue, so it is either a design flaw or a programming issue, in any event it is a safety feature that is not working as described or as in other gm cars I own. They are not willing to discuss it anymore because even though it does not work in the field for him or me, their engineer said it is working as designed.