Unable to disable user interface key names for translation

Summary

According to Choosing a Default Language, you can append ?i18ntranslate=on to the end of your Confluence URL in order to enable user interface key names for translation. To disable it, you are supposed to be able to change it to ?i18ntranslate=off and it will remove the key names.

Environment

Confluence Server

Steps to Reproduce

1. Navigate to Confluence Server instance, log in.
2. Change URL to https://confluence.server?i18ntranslate=on
3. Notice the key names have been added:
4. Now, change URL back to https://confluence.server?i18ntranslate=off
5. Key names should be removed

Expected Results

Key names should be removed after ?i18ntranslate=off is appended.

Actual Results

They are not always being removed. In fact, I am not able to remove them at all from my instance.

Workaround

No current workaround.