We assume that random siren firing was caused by lack of the rubber bumper under the hood (I cannot even get it from the local dealer as this version is not available on Polish market). We replaced it with makeshift rubber-ish part but it's not perfect.. That's why we disconnected the siren.
I haven't checked if hazard lights blinks when opening the passenger door as I always notice it then sitting behind the wheel
The self locking mechanism (when doors are not opened after unlocking) works perfectly..
For me it looks like anti theft system would like to 'tell me' that it was engaged when I was not there.
I will try to record a video today to show it in more details.