DNG from DNGConverter..some read..some don't

I have still camera raw files that I need to load in color grading software

I convert the raw files to DNG

Some are readable in the color grading software (baselight), while others aren't

I tried davinci resolve & its the same.

Of course all work in adobe products.

Its appears the certain cameras are the culprit.

Nikon nefs from d800 aren't readable but from D300 are readable.

Could I be missing something?

Any suggestions?

thanks,

TomT