Some Nuget targetFramework metadata does not have the same makeup as others

While testing NEXUS-12484, I loaded https://www.nuget.org/packages/Elasticsearch.Net/ (5.2.0) into the default nuget.org-proxy. I noticed the targetFramework metadata displayed link this:

::net45|::net46|NETStandard.Library:1.6.0:netstandard1.3|System.Collections.Specialized:4.0.1:netstandard1.3|System.Runtime.Serialization.Primitives:4.1.1:netstandard1.3|Microsoft.CSharp:4.0.1:netstandard1.3|System.Dynamic.Runtime:4.0.11:netstandard1.3|System.Reflection.TypeExtensions:4.1.0:netstandard1.3|System.ComponentModel.TypeConverter:4.1.0:netstandard1.3

However, this seems to be missing the >= markup present in other packages.
For example, "NETStandard.Library (>= 1.6.0)" is listed and we show "NETStandard.Library:1.6.0:netstandard1.3" but I feel that should be "NETStandard.Library:[1.6.0, ):netstandard1.3".

Compare with https://www.nuget.org/packages/AutoMapper/4.2.0

::portable45-net45+win8+wpa81|::net45|Microsoft.CSharp:[4.0.0, ):dotnet5.1|System.Collections:[4.0.10, ):dotnet5.1|System.Collections.Concurrent:[4.0.10, ):dotnet5.1|System.Collections.Specialized:[4.0.0, ):dotnet5.1|System.ComponentModel.TypeConverter:[4.0.0, ):dotnet5.1|System.Diagnostics.Debug:[4.0.10, ):dotnet5.1|System.Dynamic.Runtime:[4.0.10, ):dotnet5.1|System.Globalization:[4.0.10, ):dotnet5.1|System.Linq:[4.0.0, ):dotnet5.1|System.Linq.Expressions:[4.0.10, ):dotnet5.1|System.Linq.Queryable:[4.0.0, ):dotnet5.1|System.ObjectModel:[4.0.10, ):dotnet5.1|System.Reflection:[4.0.10, ):dotnet5.1|System.Reflection.Emit:[4.0.0, ):dotnet5.1|System.Reflection.Emit.ILGeneration:[4.0.0, ):dotnet5.1|System.Reflection.Extensions:[4.0.0, ):dotnet5.1|System.Reflection.Primitives:[4.0.0, ):dotnet5.1|System.Reflection.TypeExtensions:[4.0.0, ):dotnet5.1|System.Runtime:[4.0.20, ):dotnet5.1|System.Runtime.Extensions:[4.0.10, ):dotnet5.1|System.Text.RegularExpressions:[4.0.10, ):dotnet5.1|System.Threading:[4.0.10, ):dotnet5.1|System.Threading.Tasks:[4.0.10, ):dotnet5.1

I did not check older NX3 at this time because of NEXUS-12484, I do not believe I could (would show as "Unsupported").