diff -r cc664a3917e2 -r 9ea5ea53744b plugins/mod_mam/mod_mam.lua
--- a/plugins/mod_mam/mod_mam.lua	Mon Sep 18 18:28:29 2017 +0200
+++ b/plugins/mod_mam/mod_mam.lua	Mon Sep 18 18:35:01 2017 +0200
@@ -294,6 +294,7 @@
 			end
 		end);
 		if #clone_for_storage.tags == 0 then
+			log("debug", "Not archiving stanza: %s (empty when stripped)", stanza:top_tag());
 			return;
 		end
 	else