Error CS0009 after compiling. Requires Unity restart

I've been getting the following error randomly after doing a recompile of my project. It seems to happen after recompiling a couple of times.

 Microsoft (R) Visual C# Compiler version 3.5.0-dev-20359-01 (8da8ba0c)
 Copyright (C) Microsoft Corporation. All rights reserved.
 
 error CS0009: Metadata file 'C:\<ProjectFolder>\Library\ScriptAssemblies\SimpleWebTransport.dll' could not be opened -- The process cannot access the file 'C:\<ProjectFolder>\Library\ScriptAssemblies\SimpleWebTransport.dll' because it is being used by another process.

The specific .dll file that it cannot open is different every time. Sometimes its Unity.timeline.dll, or Unity.Mathematics.dll, or any other random dll in the ScriptAssemblies folder

I am using Unity LTS 2020.3.33f1.

I usually use VSCode, but I tried switching to Visual Studio Community 2022 and still got the same error after recompiling a few times.

I have also reinstalled Unity, and upgraded my Unity version to the latest LTS for 2020 with no success.