Code Completion parameter options not reflecting ExpectedValues attribute settings

I am not sure what I am missing. Based on everything I have found, I should be able to limit the code completion parameter options to only those listed in the ExpectedValues attribute.

Instead, I am seeing all possible options based on the type hint.

Method Declaration:

Code Completion:

If I understand correctly, the only two items in the dropdown should be the first two. But as you can see, much more is shown. I have disabled third-party plugins, but no change. Anyone have a clue what I might be missing?

I am running 2021.1 RC, but had the same issue on 2020.3. 

I have set the Language Level to 8.0 as well.