diff -r dee24c87dbf0 -r 84ef4517de03 mercurial/templater.py
--- a/mercurial/templater.py	Thu Jul 28 08:53:36 2016 -0700
+++ b/mercurial/templater.py	Wed Jul 27 15:14:19 2016 -0500
@@ -670,7 +670,9 @@
         tzoffset = None
         tz = evalfuncarg(context, mapping, args[1])
         if isinstance(tz, str):
-            tzoffset = util.parsetimezone(tz)
+            tzoffset, remainder = util.parsetimezone(tz)
+            if remainder:
+                tzoffset = None
         if tzoffset is None:
             try:
                 tzoffset = int(tz)