diff --git a/ChangeLog b/ChangeLog
index 0b864c290..84d6af4d9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -191,6 +191,7 @@
           Boß).
 - TW-1469 Case-insensitive searching broken on Cygwin (thanks to Richard
           Boß).
+- TW-1471 task calc uses output it doesn't understand (thanks to Jens Erat).
 - Added new holidays.xy-XY.rc definition files
 - Removed deprecated 'echo.command' setting, in favor of the 'header' and
   'affected' verbosity tokens.
diff --git a/src/CLI.cpp b/src/CLI.cpp
index c5b1fee1b..fdce9fc52 100644
--- a/src/CLI.cpp
+++ b/src/CLI.cpp
@@ -647,7 +647,7 @@ void CLI::addArg (const std::string& arg)
       isID             (raw) ||     // <id>
       isPattern        (raw) ||     // /<pattern</
       isSubstitution   (raw) ||     // /<from>/<to>/[g]
-      isAttribute      (raw) ||     // <name>[.[~]<modfifier>]:<value>
+      isAttribute      (raw) ||     // <name>[.[~]<modifier>]:<value>
       isOperator       (raw))       // <operator>
   {
     _original_args.push_back (raw);
diff --git a/src/Variant.cpp b/src/Variant.cpp
index a08bf6e10..614df705f 100644
--- a/src/Variant.cpp
+++ b/src/Variant.cpp
@@ -2062,21 +2062,19 @@ void Variant::cast (const enum type new_type)
     case type_date:
       {
         _date = 0;
-        if (dateFormat != "")
+
+        ISO8601d iso;
+        std::string::size_type pos = 0;
+        if (iso.parse (_string, pos) &&
+            pos == _string.length ())
+        {
+          _date = (time_t) iso;
+        }
+        else if (dateFormat != "")
         {
           Date d (_string, dateFormat);
           _date = d.toEpoch ();
         }
-        else
-        {
-          ISO8601d iso;
-          std::string::size_type pos = 0;
-          if (iso.parse (_string, pos) &&
-              pos == _string.length ())
-          {
-            _date = (time_t) iso;
-          }
-        }
       }
       break;
     case type_duration: