2019 Q5 parking brake

Hi I got a 2019 Q5 black diesel edition in Jan 2024 and would like to know if the auto handbrake is supposed to engage automatically or not. I have found that sometimes the parking brake engages automatically and sometimes it doesn't.  I've taken it to Audi twice now and been given conflicting info stating from one person that the auto handbrake should engage automatically and then another saying i have to manually flick the parking button to get the parking brake to engage. However I have noticed on occasions thst the brake engages itself but its very inconsistent.  I've tried leaving the car in drive or reverse and sometimes it auto engages and sometimes it doesn't. I've put the car in park by pressing the P on the gear shift and sometimes it engages the handbrake  when i switch off the engine and sometimes it doesnt. We still have a 2014 A3 which has the same buttons and the auto handbrake engages whenever you stop the car and switch off the engine unless you flick the P switch to cancel it. 

I just feel it either engages or it doesn't engage and keen to find out what anyone else has experienced or if it is a fault which Audi need to find even though they said today that no fault is showing yet the technician drove the car with me and experienced the same as I had explained. Thanks in advance