Namespace missing

Hello, I just migrated an old AR project to a newer Unity version so I can bring it NRSDK compatibility. When I import the latest SDK this error appears in my console

Assets/NRSDK/Scripts/Utility/Async/AsyncTask.cs(75,24): error CS0246: The type or namespace name ‘WaitForTaskCompletionYieldInstruction<>’ could not be found (are you missing a using directive or an assembly reference?)

Has anyone else experienced this or gotten the same error?

Drop a comment below

I solved it by creating an internal class but I’m still curious to why it occurred in the first place