When I convert a Panasonic FZ-200 .RW2 raw file using DNG Converter 8.6 on Windows 8.1 64 bit, I get a warning from ExifTool of "Invalid DistortionInfo." Looking at the ExifTool source code, this happens when the length of the block containing the distortion information is not 32 bytes in length (which it is in the .RW2 file).
This indicates to me that the DNG converter is not correctly rewriting some of the metadata correctly.
Can anybody else reproduce this, and is this the proper forum for reporting this problem?