Speaking to the family member who had this issue, the idea of “Dew point” cropped up … together with this time of year.
Say the phone was in a cold dry place for a while (in transit?) then bought to slightly humid room temperature a dew point sensor might be tripped.
The sensor may be both sensitive and persistent, hence the Samsung recommended sequence of jobs to eliminate it (bearing in mind also that maybe the phone / usb port did actually get damp or dirty).