Yes, I see the PK flashing at times particularly on 80/40 but more recently on 20M because I have improved my antenna setup. I only use the ham bands and I have no nearby AM broadcast transmitters. I don't want to criticize the FDM-DUO because it's done a superb job for me and you get what you pay for. No-one could expect it to compare with one of the high-end $4000 radios.
I was just on in the CW-Ops activity hour on 80/40/20 and I could hear the low level sqwauk of a strong stations on 40M, but I forgot to check the PK indicator at the time. I've had the Elad for several years and I hadn't even noticed the PK indicator until I started to research ADC overload..!
During the day there is some local electric fence noise - not sure if that is a contributing factor as well, on 20M.
I would be interested to hear from anyone who has that QSF unit and whether it has helped them with ADC overload on the ham bands.