Keep Coding

I have a problem with MSBuild 15 and copying to output path libraries that not included in "reference" block of NuGet package.
<metadata>
<references>
<reference file="ReferencedDLL.dll" />
</references>
</metadata>
<files>
<file src="bin\ReferencedDLL.dll" target="lib\net461" />
<!-- These ones -->
<file src="bin\SomeOtherDLLs*.dll" target="lib\net461" />
</files>
If OutputPath is relative then SomeOtherDLLs*.dll are not copied to output (ex. bin/debug). If OutputPath is absolute thats all right.
This problem appeared when I migrate my NuGet references to new <PackageReference> spec. Of course I can put $(MSBuildThisFileDirectory) in <OutputPath> property at project file
<OutputPath>$(MSBuildThisFileDirectory)\bin\$(Configuration)\</OutputPath>
or use build/*.target in package. But I can't understand why is the behavior different and these problems manifests only when using relative paths?