When editing an achievement evaluator, then clicking on the 'Save As' tab, none of the three options are selected by default. This leads to the following error if the user doesn't select any of the options.
"Don't recognize saveMode: |no_save_mode_selected|. Unknown error."
Despite this error, the file is still saved, but the achievement evaluator isn't changed, and any edits appear to be lost as the editor reverts back to the original evaluator.
I think the best fix is just to ensure that one of the three radio buttons are selected by default, but putting this as an issue to see what others thing before trying to fix it myself.