This is a crop from a SOOC JPEG produced by my EFS 17-55 on my Canon 90D. Setting aside the exposure being too dark, please look at how the fine detail of the trees has been turned into a fog:
This is not a consequence of the crop and downsizing needed to be able to post it here, I can see the same effect in the full image
This is not the only example I have of this problem. Also I never saw this problem on shots from my previous Canon body (400D) and the exact same lens. The firmware of the 90D is the latest available (v1.1.1)/
Meanwhile, this similar crop is a JPEG produced from the RAW, .CR3, file. No fog in the detail.
My Googling has not been able to find anything about Canon SOOC JPEGS messing up fine details like this. Can any one here suggest what's happening?