[humfras]

My suggestion / meine Empfehlung:

local frame = CreateFrame("Frame")
local events = {}
local incombat

local function checkerfunc()
	if not UnitBuff("player", "Schlachtruf") and not UnitBuff("player", "Befehlsruf") then
		SpellActivationOverlay_ShowOverlay(SpellActivationOverlayFrame, 6673, "INTERFACE\\ICONS\\Ability_Warrior_BattleShout.blp", "TOP", 1.1, 139, 65, 239, false, false)
	else
		SpellActivationOverlay_HideOverlays(SpellActivationOverlayFrame, 6673)
	end
end

function events:PLAYER_REGEN_ENABLED(...)
	incombat = false
	SpellActivationOverlay_HideOverlays(SpellActivationOverlayFrame, 6673)
end
function events:PLAYER_REGEN_DISABLED(...)
	incombat = true
	checkerfunc()
end

function events:UNIT_AURA(unit)
	if unit ~= "player" or not incombat then return end	--only proceed if the player has an aura event
	checkerfunc()
end

frame:SetScript("OnEvent", function(self, event, ...)
	events[event](self, ...)
end)
for k, v in pairs(events) do
	frame:RegisterEvent(k)
end