P: Can't import image scans as Lightroom thinks is duplicates

Hi Nicolai,
Are you not able to select the photo in the import screen? What message do you get when you hover over the icon?
Is it "Attempting to add multiple copies of the same file" or "This photo has already been added."?

It would also help if you send us one of the images you can't import along with some diagnostic information. I will DM you the instructions.

We have determined that the behavior is incorrect in your scenario and a bug has been logged. Thanks for reporting it. 

I have asked an engineer to look into this and respond.

Lightroom CC uses the hash to determine a files status as a duplicate. Identically named-yet distinctly different scans shouldn't result in duplicate detected status.  Stand by. 

Lightroom Classic CC is designed to recognize duplicates if the all of the following apply:

1. Filenames are identical
2. File size on disk is identical
3. Date/Time stamp is identical

It is possible to uncheck the Don't Import Suspected Duplicates option in the File Handling panel of the Import dialog.  After doing this, Lightroom should allow you to import suspected duplicates.