If I choose Layout-Print-Adobe PDF then the symbology color for my features from a file geodatabase appear.
If I choose Layout-Export-and save as an Adobe PDF, then the feature still appears, but the symbology color is lost.
The two pdf attachments show the problem. Note that 'Easements' has no color when I exported the layout, but it does have its symbology color when I print to a pdf. I didn't have this problem several months ago, so I think the problem began after the upgrading to Pro 2.2.1.
There are only limited options when exporting the layout to pdf, and none of them make a difference.
I was playing with PDF printing and found this thread helpful. But you may have seen it already.