I have just changed camera from a Canon to the Sony a73. When I was using Canon I always changed its raw files to dng files, which were smaller than Canon raw files. With the Sony, however,
Is this a bug in the dng conversion process?
LR Classic 7.4, Windows 10 64 bit, 12GB ram.
Nope, the DNG Converter is decompressing the compressed Raw before converting it to DNG and not recompressing. That's the way it's supposed to work. If you want compression opt for Lossy DNG (t's not as lossy as jpg compression).