targetFramework attribute in NuGet nuspec file is rendered as Unsupported

Nexus does not correctly parse the targetFramework attribute from the nuspec file when we push an artifact to the nuget feed hosted on Nexus. When we check the dependency attribute on the uploaded artifact, it shows "Unsupported". E.g. the following values are shown in the dependency attribute:

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

When downloading the artifact with Nexus as a proxy, it works fine what means that there are no Unsupported values but the real version mentioned there.

For me, it looks like the functionality that was built in NEXUS-6158 is broken as it doesn't just take the information that is provided from the nuspec file but is replacing that by "Unsupported" in the feed. Or is this expected behavior? It's not about having this information searchable via the API or so, it's about that it's just not there.