--- a/plugins/muc/mod_muc.lua	Tue Jul 10 21:08:32 2018 +0100
+++ b/plugins/muc/mod_muc.lua	Wed Jul 11 02:25:07 2018 +0200
@@ -158,6 +158,7 @@
 	local room = event.room
 	if room.destroying then return end
 	if not room:has_occupant() and not persistent.get(room) then -- empty, non-persistent room
+		module:log("debug", "%q empty, destroying", room.jid);
 		module:fire_event("muc-room-destroyed", { room = room });
 	end
 end, -1);