Is this a bug - tag exists returning true when it should be false

Make sure you don’t have a tag called “agenda” and then run this AppleScript

tell application “OmniFocus”
tell default document
log (tag “agenda” exists)
end tell
end tell

Why does it return true? Change it to almost anything else and I still get ‘true’. It does this for ‘decision’ as well. What’s up here? Do I have a corrupted database?