Problem definition

When a form is created in a project, it will have no default language and will always use the user's preferred language.

Suggested Solution

Set the form's language to the project's default language.

Workaround

To set the form's language to set it to default instead of using a user's preferred language, add a translation for a language that would likely not be used/selected and set the Primary Language to the language of your choice. Related doc: Add translations to a form