I convert whole folders of raw files to lossy DNG on a regular basis, and since earlier this year (at least), I've noticed a problem that affects a very small percentage of the files (sometimes it doesn't happen at all), but it's starting to become a little annoying.
The problem (when it happens) is that some of the resulting lossy DNG files look good in the Develop mode of LR Classic and in Camera Raw. Even the preview from Windows file explorer (and when using image viewers that display the embedded jpg preview) looks ok. But when displaying these problematic files from the Library module in Lightroom Classic, they show a strong purple cast. So, I think there is some problem with the preview generated by LR.
Like I said, this problem happens very rarely, but it keeps happening every now and then. Most of the times I am able to fix the "pink preview" by re-building 1:1 previews, or just removing and reimporting the file. But there must be something going on with the preview generation for lossy DNG files since I also read about it (or a very similar problem) in this thread: https://forums.adobe.com/message/10758722
I am using Windows 10 and the latest versions of Lightroom Classic CC (8.0) and Camera Raw 11.0, but this was happening already with some LR CC 7.x versions. Thanks.