When I checked the attenuation of the No Load waveform verification ATT MODEL: 00-00007A with a network analyzer, it was 34?35dB rather than 40dB. Is it defective?

When I checked the attenuation of the No Load waveform verification ATT MODEL: 00-00007A with a network analyzer, it was 34?35dB rather than 40dB. Is it defective?

Because the input Z of the No Load waveform verification ATT (MODEL:00-00007A) is as high as 2.475kΩ, connecting it directly to a 50Ω system changes its characteristics due to reflection.
When we check transmission characteristics using a network analyzer, our inspection specification requires a feed-through termination to be inserted.
Please insert a feed-through termination.