I wanted to confirm if you can update an option set value from an import? I have a client who is claiming on a managed solution, after they did an import with a spreadsheet with wrong values for an option set column, they changed one of the values of the option set to the wrong value (a value that didn't exist in the option set).
I'm under the impression the only way you can change an option set value in a managed solution is through Settings > Customizations > Customize the System as an Administrator.