diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index 3269136a32..caad44832d 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -23,6 +23,7 @@
 #ifndef __ardour_plugin_h__
 #define __ardour_plugin_h__
 
+#include <atomic>
 #include <memory>
 #include <set>
 #include <string>
@@ -425,15 +426,16 @@ private:
 	PresetRecord     _last_preset;
 	bool             _parameter_changed_since_last_preset;
 
-	PBD::ScopedConnection _preset_connection;
-
 	MidiRingBuffer<samplepos_t> _immediate_events;
+	std::atomic<bool>           _resolve_midi;
 
 	void invalidate_preset_cache (std::string const&, Plugin*, bool);
 	void resolve_midi ();
 
 	PluginInsert* _pi;
 	uint32_t      _num;
+
+	PBD::ScopedConnection _preset_connection;
 };
 
 struct PluginPreset {
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index 3f5b92347b..4140f6b6bc 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -95,6 +95,7 @@ Plugin::Plugin (AudioEngine& e, Session& s)
 	, _have_pending_stop_events (false)
 	, _parameter_changed_since_last_preset (false)
 	, _immediate_events(6096) // FIXME: size?
+	, _resolve_midi (false)
 	, _pi (0)
 	, _num (0)
 {
@@ -116,6 +117,7 @@ Plugin::Plugin (const Plugin& other)
 	, _last_preset (other._last_preset)
 	, _parameter_changed_since_last_preset (false)
 	, _immediate_events(6096) // FIXME: size?
+	, _resolve_midi (false)
 	, _pi (other._pi)
 	, _num (other._num)
 {
@@ -427,6 +429,11 @@ Plugin::connect_and_run (BufferSet& bufs,
 			}
 		}
 
+		bool canderef (true);
+		if (_resolve_midi.compare_exchange_strong (canderef, false)) {
+			resolve_midi ();
+		}
+
 		if (_have_pending_stop_events) {
 			/* Transmit note-offs that are pending from the last transport stop */
 			bufs.merge_from (_pending_stop_events, 0);
@@ -440,21 +447,21 @@ Plugin::connect_and_run (BufferSet& bufs,
 void
 Plugin::realtime_handle_transport_stopped ()
 {
-	resolve_midi ();
+	_resolve_midi = true;
 }
 
 void
 Plugin::realtime_locate (bool for_loop_end)
 {
 	if (!for_loop_end) {
-		resolve_midi ();
+		_resolve_midi = true;
 	}
 }
 
 void
 Plugin::monitoring_changed ()
 {
-	resolve_midi ();
+	_resolve_midi = true;
 }
 
 void