diff --git a/lemon/lgf_reader.h b/lemon/lgf_reader.h
--- a/lemon/lgf_reader.h
+++ b/lemon/lgf_reader.h
@@ -870,7 +870,9 @@
       while (readSuccess() && line >> c && c != '@') {
         readLine();
       }
-      line.putback(c);
+      if (readSuccess()) {
+        line.putback(c);
+      }
     }
 
     void readNodes() {
@@ -1699,7 +1701,9 @@
       while (readSuccess() && line >> c && c != '@') {
         readLine();
       }
-      line.putback(c);
+      if (readSuccess()) {
+        line.putback(c);
+      }
     }
 
     void readNodes() {
@@ -2226,7 +2230,9 @@
       while (readSuccess() && line >> c && c != '@') {
         readLine();
       }
-      line.putback(c);
+      if (readSuccess()) {
+        line.putback(c);
+      }
     }
 
   public:
@@ -2567,7 +2573,9 @@
       while (readSuccess() && line >> c && c != '@') {
         readLine();
       }
-      line.putback(c);
+      if (readSuccess()) {
+        line.putback(c);
+      }
     }
 
     void readMaps(std::vector<std::string>& maps) {