If you load multiple files in a fsx script with the same filename but different path everything works OK. (Try executing dotnet fsi working.fsx).
But, if you create a load-script.fsx and you load the same files from different directories in it and #load "load-script.fsx" then you get an error
error FS0239: An implementation of the file or module 'FSI_0001_Person' has already been given
Try executing dotnet fsi not-working.fsx.
The problem appears to have to do something with namespaces. If both files define namespaces (with different names) the load-script does not work but if you change one of the files to define module then it works again.