If you’ve already unchecked “Allow topics to have tags” and the tags field is still appearing, it’s usually caused by one of the following:

First, clear all caching (plugin cache, server cache, and browser cache) and then refresh the page. Sometimes the old form layout is being cached.

If that doesn’t fix it, temporarily switch to a default WordPress theme. Some themes override bbPress templates and manually include the tag field, which makes it appear even when disabled in settings.

Also try disabling other plugins briefly—especially SEO, forum add-ons, or customization plugins—to check for a conflict.

If the setting still doesn’t apply, go back to Settings → Forums, enable the option, save, then disable it again and save once more. Occasionally the option doesn’t update properly until it’s re-saved.

If none of that works, it’s most likely a theme template override forcing the tag field to display.