Wrong resolution when different targets depend on conflicting versions

Description

I'm trying to install dotNetRDF in a project which targets .NET Standard 1.5 and 2.0. That package depends on another which has mutually exclusive restrictions for those two targets. Here's a excerpt from the lock file

NUGET
  remote: https://www.nuget.org/api/v2
    dotNetRDF (2.0.1)
      Microsoft.Extensions.Configuration (>= 1.1.2) - restriction: && (< net40) (>= netstandard1.4) (< netstandard2.0)
      Microsoft.Extensions.Configuration (>= 2.0) - restriction: && (< net40) (>= netstandard2.0)

Using Paket version 5.167.1

Repro steps

Here's an example repository:

ClassLibrary1.zip

Unzip and run dotnet restore

Expected behavior

Version 1.1.2 should be used by netstandard1.5 target
Version 2.0 should be used by netstandard2.0 target

Actual behavior

dotnet restore fails because Paket tries to apply version >= 2.0 to both targets

error NU1202: Package Microsoft.Extensions.Configuration 2.0.2 is not compatible with netstandard1.5 (.NETStandard,Version=v1.5). Package Microsoft.Extensions.Configuration 2.0.2 supports: netstandard2.0 (.NETStandard,Version=v2.0) [C:\Projects\temp\ClassLibrary1.sln]
  Restore failed in 843,19 ms for C:\Projects\temp\ClassLibrary1\ClassLibrary1.csproj.

Unzip the provided ClassLibrary1.zip reproduction and run dotnet restore with Paket 5.167.1, then inspect the lock file entries for Microsoft.Extensions.Configuration across the netstandard1.5 and netstandard2.0 targets. Done means the restore selects version 1.1.2 for netstandard1.5 and version 2.0 for netstandard2.0 without the NU1202 compatibility error.