diff --git a/rtengine/dcrop.cc b/rtengine/dcrop.cc
index 56248e4fa..0005d552e 100644
--- a/rtengine/dcrop.cc
+++ b/rtengine/dcrop.cc
@@ -1055,6 +1055,7 @@ void Crop::update(int todo)
                 lightCurveloc2.clear();
                 cclocalcurve2.clear();
                 exlocalcurve2.clear();
+                lmasklocalcurve2.clear();
                 hltonecurveloc2.clear();
                 shtonecurveloc2.clear();
                 tonecurveloc2.clear();
diff --git a/rtengine/improccoordinator.cc b/rtengine/improccoordinator.cc
index b112104aa..652c5a9b6 100644
--- a/rtengine/improccoordinator.cc
+++ b/rtengine/improccoordinator.cc
@@ -1059,6 +1059,7 @@ void ImProcCoordinator::updatePreviewImage(int todo, bool panningRelatedChange)
                 lightCurveloc.clear();
                 cclocalcurve.clear();
                 exlocalcurve.clear();
+                lmasklocalcurve.clear();
                 hltonecurveloc.clear();
                 shtonecurveloc.clear();
                 tonecurveloc.clear();
diff --git a/rtengine/simpleprocess.cc b/rtengine/simpleprocess.cc
index e8c7ec2a2..643b5b0be 100644
--- a/rtengine/simpleprocess.cc
+++ b/rtengine/simpleprocess.cc
@@ -1247,6 +1247,7 @@ private:
                 cclocalcurve.clear();
                 exlocalcurve.clear();
                 hltonecurveloc.clear();
+                lmasklocalcurve.clear();
                 shtonecurveloc.clear();
                 tonecurveloc.clear();
                 lightCurveloc.clear();