Probuilder ArgumentNullException error after updating Unity from 2018.4.2 to 2018.4.8

After updating Unity from 2018.4.2 to 2018.4.8 I'm getting a varying number of errors when entering/exiting play mode or opening a scene in the editor.

Any clues on how to fix this? Full error is below:


ArgumentNullException: Value cannot be null.
Parameter name: list
System.ThrowHelper.ThrowArgumentNullException (System.ExceptionArgument argument) (at <df7127ba07dc446d9f5831a0ec7b1d63>:0)
System.Collections.ObjectModel.ReadOnlyCollection`1[T]..ctor (System.Collections.Generic.IList`1[T] list) (at <df7127ba07dc446d9f5831a0ec7b1d63>:0)
UnityEngine.ProBuilder.ProBuilderMesh.get_faces () (at Library/PackageCache/com.unity.probuilder@4.1.0/Runtime/Core/ProBuilderMesh.cs:208)
UnityEngine.ProBuilder.ProBuilderMesh.InvalidateCaches () (at Library/PackageCache/com.unity.probuilder@4.1.0/Runtime/Core/ProBuilderMesh.cs:237)
UnityEngine.ProBuilder.ProBuilderMesh.OnAfterDeserialize () (at Library/PackageCache/com.unity.probuilder@4.1.0/Runtime/Core/ProBuilderMeshFunction.cs:19)
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)