Seems a bit of an odd suggestion to say that it will turn itself off....
Usually, when the airbag light is illuminated/flashing beyond its initial self-test, it indicates some sort of fault or deployment condition. I'm not aware of a mode where it will clear in 3 days, sounds like a fob off to me!
You mention the car was repaired. Was it involved in a crash or impact at all, did any of the airbags deploy?
Reading the service manual, the flashes might indicate what’s actually at fault if its dropped itself into diagnostics mode. The flashes are 0.5 seconds apart and if there are multiple faults, it will pause for 2 seconds before flashing again.
Turn off the ignition, then turn it back on and count the flashes that appear in quick succession and count again if there is a small pause.
However ff the flashing is steady and repeating then this maybe appropriate. At no point does it state the fault self clears after a number of days (although it does state that the system can self clear if it detects the fault is no longer present).