diff --git a/libs/ardour/ardour/tempo.h b/libs/ardour/ardour/tempo.h
index fd49037307..197c8c5f8f 100644
--- a/libs/ardour/ardour/tempo.h
+++ b/libs/ardour/ardour/tempo.h
@@ -249,7 +249,6 @@ class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
 	framepos_t frame_at_pulse (const double& pulse) const;
 
 	Timecode::BBT_Time legacy_bbt () { return _legacy_bbt; }
-	bool legacy_end () { return _legacy_end; }
 
   private:
 
@@ -283,7 +282,6 @@ class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
 	bool _locked_to_meter;
 	bool _clamped;
 	Timecode::BBT_Time _legacy_bbt;
-	bool _legacy_end;
 };
 
 typedef std::list<MetricSection*> Metrics;
diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index 240be1b9e1..c04f6803fd 100644
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -158,7 +158,6 @@ TempoSection::TempoSection (const XMLNode& node, framecnt_t sample_rate)
 	, _active (true)
 	, _locked_to_meter (false)
 	, _clamped (false)
-	, _legacy_end (false)
 {
 	LocaleGuard lg;
 
@@ -201,19 +200,22 @@ TempoSection::TempoSection (const XMLNode& node, framecnt_t sample_rate)
 
 	if (node.get_property ("end-beats-per-minute", _end_note_types_per_minute)) {
 		if (_end_note_types_per_minute < 0.0) {
-			info << _("TempoSection XML node has an illegal \"in-beats-per-minute\" value") << endmsg;
-			//throw failed_constructor();
-			_end_note_types_per_minute = _note_types_per_minute;
-			_legacy_end = true;
+			info << _("TempoSection XML node has an illegal \"end-beats-per-minute\" value") << endmsg;
+			throw failed_constructor();
 		}
-	} else {
-		_legacy_end = true;
 	}
 
 	TempoSection::Type old_type;
 	if (!node.get_property ("tempo-type", old_type)) {
+		/* sessions with a tempo-type node contain no end-beats-per-minute.
+		   if the legacy node indicates a constant tempo, simply fill this in with the
+		   start tempo. otherwise we need the next neighbour to know what it will be.
+		*/
+
 		if (old_type == TempoSection::Constant) {
 			_end_note_types_per_minute = _note_types_per_minute;
+		} else {
+			_end_note_types_per_minute = -1.0;
 		}
 	}
 
@@ -4649,7 +4651,7 @@ TempoMap::set_state (const XMLNode& node, int /*version*/)
 					break;
 				}
 
-				if (t->legacy_end()) {
+				if (t->end_note_types_per_minute() < 0.0) {
 					fix_legacy_end_session();
 					break;
 				}