Some DNG files (about 3 out of 1000) don't display correctly in Lightroom Classic (10.4 202108071231-af9219b9 for Win10 64bit) and Photoshop (22.5.1 20210907.r.441 de74e1a x64) since August. I was able to fix the problem for some images by removing the photos from the lightroom library, deleting the camera raw cache and then use "Synchronize Folder" to import the photo. Then it was displayed correctly. In other cases this didn't work. Other software was showing the photo correctly (windows photos app, nomacs). The md5 sum of the files was identical. The fotos were shown correctly before I pressed "Embedded Preview" in Lightroom. For some photos (not shown correctly) it worked again, when I switched between grid view and loup view back and forth several times. Lightroom and Photoshop didn't display a warning about a broken file. You can see one effected file and a screenshot of it in the attachments. The DNG files was copied from the sdcard. So the camera produced the file, it was not converted. Somehow I can't upload the dng file here. I alwayhs get the following error:
Correct the highlighted errors and try again.The attachment's 20210916-l1002973.dng content type (image/DNG) does not match its file extension and has been removed.