Degassing Valve Visual Appearance

I have seen some samples where the coffee valve creates a noticeable "dent" or impression on the front of the bag, disrupting the design.
Question: Is this mark caused by the pressure of the valve application machine? Can we adjust the pressure to make the valve invisible from the outside, or does that risk the valve falling off?

Yes, it's caused by the pressure of the valve welding machine, it's the same conditions with bag heat sealing, temperature, pressure, heating time are all necessary for the well welding.
We can adjust the pressure to be a little bit less, but impossible to be 100% flat, 0 pressure.
What we can do is try the best to make it as smooth as it can.