I have a "equip on target" test setup outfit called "Heal-AR" . I set it to Ironforge guard for the test.

When I select it, the gear swap works, but when I hit ESC to clear target, I get this wow UI error

The equip on target code is the default

-- $EVENTS PLAYER_TARGET_CHANGED
-- $DESC Equips the outfit when your target changes to the specified name

-- $SETTING targetName = {type="string", label="Target name"}

-- Equip if it's the specified target
if UnitName("target"):lower() == setting.targetName:lower() then
    equip = true
end

Stale issue message

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