Upgrading from Lightweight RP to Universal RP via package manager does not remove Lightweight RP

To reproduce:
1. Create a new project in 19.2.4f1
2. Install Universal RP (Lightweight RP) in it
3. Open the project in a new version of unity
4. In package manager, manually upgrade the package to a new version.
5. Reopen unity
Expected result: Project upgrades cleanly, both after step 4 and after step 5
Actual result: Guid errors are thrown, due to two versions of the package existing.

Reproduced with: 2019.3.0b2

Reproducing with earlier version (2019.3.0b1) instead throws there errors:

Exception: Cannot load. Incorrect path: Packages/com.unity.render-pipelines.universal/Shaders/Utils/Blit.shader Null returned.
UnityEngine.Rendering.ResourceReloader.Load (System.String path, System.Type type, System.Boolean builtin) (at Library/PackageCache/com.unity.render-pipelines.core@7.0.1/Runtime/Utilities/ResourceReloader.cs:153)
UnityEngine.Rendering.ResourceReloader.SetAndLoadIfNull (System.Object container, System.Reflection.FieldInfo info, System.String path, System.Boolean builtin) (at Library/PackageCache/com.unity.render-pipelines.core@7.0.1/Runtime/Utilities/ResourceReloader.cs:162)
UnityEngine.Rendering.ResourceReloader.ReloadAllNullIn (System.Object container, System.String basePath) (at Library/PackageCache/com.unity.render-pipelines.core@7.0.1/Runtime/Utilities/ResourceReloader.cs:45)
UnityEngine.Rendering.ResourceReloader.ReloadAllNullIn (System.Object container, System.String basePath) (at Library/PackageCache/com.unity.render-pipelines.core@7.0.1/Runtime/Utilities/ResourceReloader.cs:36)
UnityEngine.Rendering.Universal.ForwardRendererData.OnEnable () (at Library/PackageCache/com.unity.render-pipelines.universal@7.0.1/Runtime/ForwardRendererData.cs:90)

Reproduced on: 2019.3.0b1
Also tested on 2020.1.0a3, however a different set of errors is thrown there.