--- a/mod_muc_inject_mentions/mod_muc_inject_mentions.lua	Mon Dec 21 19:29:04 2020 +0100
+++ b/mod_muc_inject_mentions/mod_muc_inject_mentions.lua	Tue Dec 22 11:18:46 2020 +0100
@@ -251,7 +251,7 @@
             "reference", {
                 xmlns=reference_xmlns,
                 begin=tostring(mention.first - 1), -- count starts at 0
-                ["end"]=tostring(mention.last - 1),
+                ["end"]=tostring(mention.last),
                 type="mention",
                 uri="xmpp:" .. mention.bare_jid,
             }