Addressables 0.6.6-preview upgrade errors

After the upgrade i'm seeing the following errors

Code (csharp):

1. Library/PackageCache/com.unity.addressables@0.6.6-preview/Runtime/ResourceManager/AsyncOperations/IAsyncOperation.cs(114,32): error CS0433: The type 'Task<TResult>' exists in both 'System.Threading, Version=1.0.2856.102, Culture=neutral, PublicKeyToken=31bf3856ad364e35' and 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Code (CSharp):

1. Library/PackageCache/com.unity.addressables@0.6.6-preview/Runtime/ResourceManager/ResourceProviders/CachedProvider.cs(55,43): error CS0433: The type 'Task<TResult>' exists in both 'System.Threading, Version=1.0.2856.102, Culture=neutral, PublicKeyToken=31bf3856ad364e35' and 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Code (CSharp):

1. Library/PackageCache/com.unity.addressables@0.6.6-preview/Runtime/ResourceManager/AsyncOperations/AsyncOperationBase.cs(63,39): error CS0433: The type 'Task<TResult>' exists in both 'System.Threading, Version=1.0.2856.102, Culture=neutral, PublicKeyToken=31bf3856ad364e35' and 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Solved below.

 

Solved! . It looks like we were using a package that had System.Threading.dll. That being said, I'm not sure why the 0.6.6 was the issue.