diff --git a/chainladder/core/triangle.py b/chainladder/core/triangle.py
index 12b0afca..442206ce 100644
--- a/chainladder/core/triangle.py
+++ b/chainladder/core/triangle.py
@@ -670,8 +670,10 @@ def grain(self, grain="", trailing=False, inplace=False):
         obj = self.dev_to_val()
         if ograin_new != ograin_old:
             freq = {"Y": "A", "S": "2Q"}.get(ograin_new, ograin_new)
-            if trailing or obj.origin.freqstr[-3:] != "DEC":
+            print(trailing, obj.origin.freqstr[-3:])
+            if trailing or (obj.origin.freqstr[-3:] != "DEC" and ograin_old != 'M'):
                 origin_period_end = self.origin[-1].strftime("%b").upper()  
+                print(origin_period_end)
             else:
                 origin_period_end = "DEC"
             indices = (