diff --git a/liberty/FuncExpr.cc b/liberty/FuncExpr.cc
index 91139a44..67de253c 100644
--- a/liberty/FuncExpr.cc
+++ b/liberty/FuncExpr.cc
@@ -254,8 +254,12 @@ FuncExpr::bitSubExpr(int bit_offset)
 	return makePort(port);
       }
       else {
-	LibertyPort *port = port_->findLibertyMember(bit_offset);
-	return makePort(port);
+        if (bit_offset < port_->size()) {
+          LibertyPort *port = port_->findLibertyMember(bit_offset);
+          return makePort(port);
+        }
+        else
+          return nullptr;
       }
     }
     else
diff --git a/liberty/Liberty.cc b/liberty/Liberty.cc
index aad0a8bd..364e5dae 100644
--- a/liberty/Liberty.cc
+++ b/liberty/Liberty.cc
@@ -130,15 +130,13 @@ LibertyLibrary::~LibertyLibrary()
   wireloads_.deleteContents();
   wire_load_selections_.deleteContents();
   delete units_;
+  // Also deletes default_ocv_derate_
   ocv_derate_map_.deleteContents();
 
   delete buffers_;
   delete inverters_;
   driver_waveform_map_.deleteContents();
   delete driver_waveform_default_;
-
-  delete default_ocv_derate_;
-  default_ocv_derate_ = nullptr;
 }
 
 LibertyCell *
diff --git a/liberty/LibertyReader.cc b/liberty/LibertyReader.cc
index 06288752..dd730770 100644
--- a/liberty/LibertyReader.cc
+++ b/liberty/LibertyReader.cc
@@ -4909,7 +4909,7 @@ LibertyReader::visitWhen(LibertyAttr *attr)
                       false, "when", attr);
     }
   }
-  if (timing_) {
+  if (timing_ && !in_ccsn_) {
     const char *func = getAttrString(attr);
     if (func) {
       TimingArcAttrs *attrs = timing_->attrs().get();