It's difficult to tell from a distance, but the oscilloscope shows some effect, suggesting it's working properly. Being a passive device, you can't compare it to a regular distortion module like the Clipping Cat 3U, which has a much more pronounced distortion effect.
You can refer to the video below to see and hear what you can expect from the passive Workmate Clipping Cat:
Hey Scott, It is normal for it to become quieter as it is a passive device with no gain stage.
It is difficult to hear its behavior from the mobile phone audio signal.
Has the knob been turned all the way to the right? Did you solder it yourself, if so, are the diodes aligned correctly?
Can you feed a classic sine wave into the clipping cat and see if there is any effect on the signal? Thanks,
Stefan