--- a/plugins/mod_csi_simple.lua	Sat May 09 13:50:58 2020 +0200
+++ b/plugins/mod_csi_simple.lua	Sat May 09 17:05:46 2020 +0200
@@ -134,6 +134,7 @@
 function disable_optimizations(session)
 	filters.remove_filter(session, "stanzas/out", manage_buffer);
 	filters.remove_filter(session, "bytes/in", flush_buffer);
+	session.csi_counter = nil;
 	if session.conn and session.conn.resume_writes then
 		session.conn:resume_writes();
 	end