diff --git a/libs/evoral/src/ControlList.cpp b/libs/evoral/src/ControlList.cpp
index e1cea8e191..dfc4ae3867 100644
--- a/libs/evoral/src/ControlList.cpp
+++ b/libs/evoral/src/ControlList.cpp
@@ -1080,7 +1080,9 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double end, d
 				 * (Optimize for immediate call this cycle within range) */
 				_search_cache.left = x;
 				//++_search_cache.range.first;
-				assert(inclusive ? x >= start : x > start);
+				if (! (inclusive ? x >= start : x > start)) {
+					cerr << "Warning: failed assertion: inclusive ? x >= start : x > start in ControlList.cpp" << endl;
+				}
 				return true;
 			} else {
 				return false;
diff --git a/libs/evoral/src/Sequence.cpp b/libs/evoral/src/Sequence.cpp
index d746f470b6..3de24106d4 100644
--- a/libs/evoral/src/Sequence.cpp
+++ b/libs/evoral/src/Sequence.cpp
@@ -193,7 +193,9 @@ Sequence::const_iterator& Sequence::const_iterator::operator++()
 		const bool ret = _control_iter->list->rt_safe_earliest_event_unlocked(
 				_control_iter->x, DBL_MAX, x, y, false);
 
-		assert(!ret || x > _control_iter->x);
+		if ( !(!ret || x > _control_iter->x) ) {
+			cerr << "Warning: Assertion failed: !ret || x > _control_iter->x in Sequence.cpp" << endl;
+		}
 
 		if (ret) {
 			_control_iter->x = x;