diff --git a/tools/releasetools/rangelib.py b/tools/releasetools/rangelib.py
index 31ed83a..1638f8c 100644
--- a/tools/releasetools/rangelib.py
+++ b/tools/releasetools/rangelib.py
@@ -104,7 +104,7 @@
         if last <= s:
           last = s+1
         else:
-          monotonic = True
+          monotonic = False
     data.sort()
     self.data = tuple(self._remove_pairs(data))
     self.monotonic = monotonic
diff --git a/tools/releasetools/test_rangelib.py b/tools/releasetools/test_rangelib.py
index 853012e..1c57cbc 100644
--- a/tools/releasetools/test_rangelib.py
+++ b/tools/releasetools/test_rangelib.py
@@ -117,6 +117,7 @@
     self.assertTrue(RangeSet("").monotonic)
     self.assertTrue(RangeSet("0-4 5-9").monotonic)
     self.assertFalse(RangeSet("5-9 0-4").monotonic)
+    self.assertFalse(RangeSet("258768-259211 196604").monotonic)
 
     self.assertTrue(RangeSet(data=[0, 10]).monotonic)
     self.assertTrue(RangeSet(data=[0, 10, 15, 20]).monotonic)