For me the problem started on 12th October and affects both SUOMI-NPP and NOAA 20 ascending and descending passes between 50N and 60N; at the moment I do not receive FY-3D
I emailed OPS and they informed me that they were not aware of any anomalies in the data. I have sent them my verbose logfiles and copies of the H5 segment files associated with today's descending SUOMI-NPP pass about 10E of the UK as delivered by Tellicast.
Interestingly the HF file associated with the missing lines is always significantly smaller than its neighbours.
I have got Python working for GOES 16 under Windows 10 thanks to Ernst's guide. Hope to move on to polar orbiters soon.