I am unable to reproduce the problem with the provided example. What else is in the file?
Perhaps you using one of the reserved key names as discussed here:
https://discourse.gohugo.io/t/what-keys-can-be-passed-to-i18n-files/48243
On an unrelated note, avoid using anything but letters, numbers, and underscores in key names. It’s a good habit, allowing you to do things like my.dot_chained.identifier. That wouldn’t work with a hyphen.