This isn't necessarily a 2019 issue as I've had this problem with 2018 & 2017 as well. It has just become so irritating that I'm now deciding to put this out there and find out if it's a problem anyone else is having.
I get people sending me PDF's all of the time. It also happens with PDF's that I have scanned myself.
The issue is that when I import them into Corel Draw, they come in as blank. Sometimes they come in with small bits of gray in them. (like the file I'm going to try to attach). I am guessing that this happens when PDF's are scanned as greyscale but that still seems odd to me.
What I usually have to do is open the PDF, convert it to greyscale again and save it and then import it and it works out. It does not work if I convert the imported PDF to anything else within coreldraw.
Has anyone else had this issue? Have you figured out how to solve it?