Pack in Visual Studio fails with transitive project reference in a clean state

Visual Studio Version: 16.8.0
Steps to reproduce:
- clone master of https://github.com/AppGates/AppGates.Build.Versioning
- pack external library (it's not relevant for this scenario, but I used that repo for another issue too)
- clean referencing library
- pack referencing library
-> build error, the transitive library (project reference) is not built during pack

Expected behavior:
The transitive project reference is built, like the direct project references of the packed project.