Import error on 2018.1.1f1

@karl- When I import https://github.com/Unity-Technologies/ProBuilder-API-Examples into a fresh 2018.1.3f1 (or 2018.1.1f1) project I get the following error

Assembly has reference to non-existent assembly 'Unity.ProBuilder.Core' (Assets/ProBuilder-API-Examples/Runtime/Unity.ProBuilder.Examples.asmdef)

Prior to that I had imported probuilder and progrids via package manager

[schranzmeister]

same here, with PB 3.0.8 and 3.0.9 and Unity 2018.2.0f2

[ajinkyapuar]

Same Issue
PB 3.0.9
Unity 2018.2.5f1