--- tads3/vmtz.cpp.orig	2013-05-18 09:42:58.000000000 +0800
+++ tads3/vmtz.cpp	2026-08-15 05:45:57.000000000 +0800
@@ -1984,7 +1984,7 @@
              *   the transition in terms of the local time that was in effect
              *   up until that moment
              */
-            result->set(tcur > 0 ? tcur - 1 : tcur);
+            result->set(cur > 0 ? tcur - 1 : tcur);
             return;
         }
     }