Random errors that come and go with editor restarts

Unity Engine
1

I opened 2019.3.0a8 to record a video for a bug-report, no error logged on the console. Then closed and re-opened the editor to capture another video and Unity output the following error to the Console:

Assembly 'Packages/com.unity.ads/Editor/UnityEditor.Advertisements.dll' will not be loaded due to errors:
Unable to resolve reference 'UnityEditor.iOS.Extensions.Xcode'. Is the assembly missing or incompatible with the current platform?
Reference validation can be disabled in the Plugin Inspector.

The platform was set to PC Standalone, I don’t have iOS Platform Support installed and Services/Ads is disabled. The project wasn’t changed between editor restarts.

I’ve seen this (not this particular error, but other ones ) a few times by now. Newer Unity versions seem to generate random errors that come and go as you restart the editor.

Is this something Unity Technologies have on their radar? Unfortunately I have no reproduce, as these issues, as already said, come and go randomly.

2

So… after I recreated a new project to submit a bug-report, then opened the project a few minutes afterwards again to test something else, I’m presented with this error:

Microsoft (R) Visual C# Compiler version 2.9.1.65535 (9d34608e)
Copyright (C) Microsoft Corporation. All rights reserved.

error CS0006: Metadata file 'C:/Users/crash/Documents/BugReport_SceneView_Profiler/Library/PackageCache/com.unity.ext.nunit@1.0.0/net35/unity-custom/nunit.framework.dll' could not be found

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