Your car has not somehow gotten locked? If I go up to my etron with the fob in my pocket and the car is locked, if I quickly pull on the handle the alarm will sound. I have to use the touch-unlock first.In my old Audi the car would automatically unlock when I approach it. This does not happen with the etron.
Happened to me too. Just once. Apparently this is a known software bug: the subroutine that unlocks the car senses the fob in your pocket, but the subroutine that disables the alarm is not notified quickly enough. I was advised to be "more deliberate" (i.e., move more slowly) when opening the car.
This has happened to us about 5 times. We did just get the service campaign completed (I think there was a part that was supposed to be ordered but that had to do with the tail light LED warning (the center segment to be replaced). However, that car is at another house so I haven't been able to confirm if that S/W update solved the alarm going off for no apparent reason issue....did you have the service campaign completed (if your car was eligible)? You can figure this out on myAudi (but copy your VIN number from the landing page since they for whatever reason don't just insert it as a parameter when you look up service recalls from your own account - lame....
Just another possibility is if you use your left hand to open the doors on the drivers side. If you look at the resting point of your thumb, it is right near or over the spot on the door handle for locking the vehicle. The software may have a difficult time determining the mode of alarm if your thumb is resting on that spot (off door unlocked or door locked alarm on). That being said I have only had it happen twice since I have had the vehicle (6 months).
Happened to me again two days ago. Second time in 4 months. Exact same scenario, approaching car from the rear left: as soon as I opened the driver's door, the alarm started screaming. My dealer doesn't know anything about it. What else is new...
You might try touch testing the door before you try to open it. If you touch it and the light flashes once, then you are good to go. If it flashes twice and beeps, you have armed and locked the car. Another touch should then make it flash once and unlock it for you.
The few times this happened to me was when I quickly walked up to the car, grabbed the handle, and quickly opened it. I assume there wasn't enough time for the software to register the key fob before I popped the door open. Now I just wait a second.