SGP30 - I2C communication fails

Hi,
I discovered an issue with a SGP30 sensor (Sensirion) that does not make 
sense to me or the manufacturer of the sensor.

1. I designed a PCB with a SGP30 on it. Everything on the PCB works, 
power rails are stable.

2. All the other ICs respond to an I2C request. Just the SGP30 is 
missing.

3. When I connect the development board for the SGP30 to a debug header, 
that sensor gets detected. The development board works on 3.3V.

4. I took off everything from the development board and jumpered some 
connections. So really all that is left is the sensor itself. When 
connecting it to a debug header, the sensor gets detected.

5. I checked the pinout and the connections of the sensor on my board. I 
also probed it against the pins of the sensor on the development board. 
Both sensors are exactly on the same nets. The sensor is close to the 
debug header.

6. The sensor went through a standard SMT reflow process (twice). I 
tried to hand solder a new sensor on it, but this did not work either.


Sensor datasheet:
https://www.mouser.com/pdfdocs/Sensirion_Gas_Sensors_SGP30_Datasheet_EN-1148053.pdf

Development board:
https://www.adafruit.com/product/3709


This just does not make sense to me at all. The only reason I can see 
that I have not verified yet is that the sensor itself got damaged 
during SMT.
Does anyone have any other ideas what I could test/ what the issue might 
be?

Thank you!