Hi, have you checked the contacts in the "A" pillar male connection?
I had this problem on my A3 PA water ingress into the socket had corroded the male pins and caused poor connection. You would do well to check both front "A" pillar looms. Before disconnecting the "A" pillar connector, you should disconnect the battery and wait 10 MINUTES, in the doors behind the card, there is a sensor with a yellow connection, generally speaking, ANY YELLOW CONNECTION IS RELATED TO VEHICLE SAFETY SYSTEMS. Removing the door connector could trick the air bag system into thinking that it's had an impact and deploy the air bags.
Regards Dave.