This codemod currently does not support legacy decorators, but we have users stuck on Ember classic that use legacy decorators (specifically, decorators in object literals).
The currently-used Flow parser does not support legacy decorators, necessitating a switch to the babel parser.
This is a bit of a yak shave.
See also: https://github.com/gitKrystan/ember-native-class-codemod/pull/1, https://github.com/gitKrystan/ember-native-class-codemod/pull/2