diff --git a/flang-rt/lib/runtime/assign.cpp b/flang-rt/lib/runtime/assign.cpp
index 86aeeaa88f2d1..bf67b5dc8b645 100644
--- a/flang-rt/lib/runtime/assign.cpp
+++ b/flang-rt/lib/runtime/assign.cpp
@@ -330,6 +330,7 @@ RT_API_ATTRS void Assign(Descriptor &to, const Descriptor &from,
       }
       flags &= ~NeedFinalization;
       toElementBytes = to.ElementBytes(); // may have changed
+      toDerived = toAddendum ? toAddendum->derivedType() : nullptr;
     }
   }
   if (toDerived && (flags & CanBeDefinedAssignment)) {