DS7 No acoustic signal of the front parking sensors when driving backwards

I noticed that in rear shunting the front parking sensors do not trigger an acoustic warning signal. However, the optical warning in the display works. Thus, in reverse I can iron everything with my front car without getting an acoustic warning.Today the DS7 is in the workshop. I just got the call from PSA that this behavior is strangely normal with the DS7. The workshop would also have checked other DS7. If this is the case, I would have noticed that the front parking sensors do not trigger an acoustic warning signal. r case is the DS7 has a tangible software stack, which hopefully will be turned off quickly. Is this error also present with you? Or does the Macke only connect with the so-called 360° camera? Thank you and greeting Franz