User Field Prompt allows you to show a user field form in any Discourse post. Changes made in the form will be saved in the current user profile. Itās useful to ask users to make changes to a user field without having to force them to search the field in their profile.
Usage for a user field named age and another one named best fruits:
I think the problem is that your site is running a legacy version of the post-stream, because discourse-nationalflags has not yet been updated for the new post stream. As an admin, you should be seeing a red banner about that issue.
The recent fixes for user-field-prompt were built only with the new post-stream in mind, so thatās why itās causing errors on your site.
So if you need this user-field feature right now, Iād recommend disabling the nationalflags plugin. Otherwise, youāll need to wait for the developer of that plugin to make the necessary updates.