Problem with LRc and Topaz Photo AI handling dng/DNG files

Hello,

I am having a problem with using Topaz Photo AI (versions 4.0 and 4.01) with LRc (version 14.3.1) on my Dell laptop (Windows 11, version 24H2).  I suspect that the problem lies with Topaz, but it is certainly related to a change in how LR handled converions from native RAW files to DNG files, so I'm looking for any info that I might be able to pass on to them.  Or, perhaps there is more going on here than meets the eye, and Adobe shares some responsibiltiy.

I convert my RAW files to dng while importing them.  I have been doing this since I started using LR v 2 in 2006.   Sometime between September 16, 2017 and October 28, 2017 LR started saving my imported files with a DNG (uppercase) extension, rather than the dng (lowercase) extension used previously.  Since the  choice of lowercase or uppercase extensions is in LR preferences, I must have changed this, athough I can't recall doing so.  It certainly shouldn't make a difference.  However,  in every case the files with the DNG extension, when processed through Photo AI, result in files that have none of the original metadata.  The only metadata they have is the capture date, which is not the original date, but the date the file was created in Photo AI.  All the data about camera settings, lenses, ratings, etc. is absent.  With the earlier files, with dng extensions, all of the original metadata is preserved in the Photo AI file.