date.formats are reported as having broken data

```
thor locales:test some_locale
```
wrongly reports

```
The following keys have broken data:
date.formats.default
date.formats.long
date.formats.short
```
I have checked **zh-CN** and **fr** locales the error is given when the keys are clearly not broken.

Testing the **en** locale also reports these keys as having broken data.