.assembly extern retargetable mscorlib
{
.publickeytoken = (7C EC 85 D7 BE A7 79 8E ) // |.....y.
.ver 2:0:5:0
}

If any assemblies loaded by MetadataLoadContext were built against some older versions of mscorlib, PathAssemblyResolver will fail to match any newer versions of mscorlib present in assemblyPaths, due to a public key token mismatch. PathAssemblyResolver already supports taking the most recent version for target assemblies with an empty public key token.

https://github.com/dotnet/corefx/blob/master/src/System.Reflection.MetadataLoadContext/src/System/Reflection/PathAssemblyResolver.cs#L80

Add support for most-recent assembly match when assembly being resolved is 'retargetable'.