Black ribbon/area on thumbnail previews: WHY?
Hello Guys, hope someone mind give me a hand here.
This is not a problem at all, just a small thing that gets to my nerves now and then, LOL.
The thing is that SOMETIMES I get a black area inside the thumbnail preview, exactly like this:

These documents were all scanned on the same scanner using exactly the same settings, so exactly what is causing this behavior on the thumbnail preview? Any ideas? I've got Windows 10 1809 and Adobe Acrobat DC 2015 going.
One thing to note is that this "black area" is not present when the PDF is opened, it only shows on the thumbnail 😕😕
Thanks
VBrt
