Flicker noise is related to crystal surface defects in semiconductors, and can be found in any semiconductor device.
But because flicker noise is proportional with bias current, this makes somehow the active devices to have higher flicker noise power.
Mixer DSB NF includes signal and noise inputs from both sidebands.
Mixer SSB NF assumes signal input from only one sideband, but noise inputs from both sidebands. Using an image filter to eliminate the image response (to do accurate NF measurement) does not help because it changes the image-frequency embedding impedance, changing the noise temperature.
This is the reason that in the device specifications is mentioned what type of NF was measured, SSB or DSB.