Importing DNG file from memory card shown corrupted in Lightroom

Memory card to reader to computer, at random, one or two or more DNG files that are imported imported are shown as corrupted in the desktop Lightroom application (MacOS).  

in camera the files are fine, when I export from the camera to the native mobile app (iOS) then export from the photos app into Lightroom mobile (iOS) the file are not corrupted. 

this has happened at random with Lightroom and Lightroom CC.. why are they displayed as a corrupted file when the file is not corrupted.

multiple premium SD cards/brands and readers were tested to see if it was an issue with the media, and they've all had issue upon importing into Lightroom