DNGs output by DeNoise and Sharpen aren't compressed

When I save a file from DeNoise/Sharpen, it may be around 120MB (for example).

If I use Lightroom Classic’s menu item “Library” > “Convert Photo to DNG…” (with lossless compression) the DeNoise/Sharpen DNG files are reduced from 120MB to around 90MB. This tells me there’s lossless compression that could be done by DeNoise/Sharpen without me having to do the extra step in Lightroom Classic to compress the files.