Possible bug? Change CF type

I need to change a CF type from Select One to Combobox. When I make the change
in the configuration it comes back saying “CustomField Environment: That is
already the current value”. When I go to test the changes the type is changed
from Select One to Enter One Value. I’m not given the option of either entering
a value or selecting from a dropdown. How do I make this change? Or is this a bug?

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