diff --git a/src/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp b/src/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp
index 8d96301947..ca898ca307 100644
--- a/src/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp
+++ b/src/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp
@@ -169,6 +169,8 @@ preclaimUpdate(PreclaimContext const& ctx, AccountID const& account, uint256 con
         }
     }
 
+    XRPL_ASSERT(sleVault, "xrpl::LoanBrokerSet::preclaimUpdate : sleVault is initialized");
+
     if (account != sleBroker->at(sfOwner))
     {
         JLOG(ctx.j.warn()) << "Account is not the owner of the LoanBroker.";
diff --git a/src/test/app/LoanBroker_test.cpp b/src/test/app/LoanBroker_test.cpp
index aa4cf59421..e7892fd68f 100644
--- a/src/test/app/LoanBroker_test.cpp
+++ b/src/test/app/LoanBroker_test.cpp
@@ -1951,6 +1951,16 @@ class LoanBroker_test : public beast::unit_test::suite
                 ter(temINVALID),
                 THISLINE);
         }
+
+        // Pre-amendment: zero VaultID on update → temINVALID
+        {
+            testcase("LoanBrokerSet pre-amendment: zero VaultID on update");
+            Env env(*this);
+            env.disableFeature(fixLendingProtocolV1_1);
+            auto const [vaultID, brokerKL] = setup(env);
+
+            env(set(alice, uint256{}), loanBrokerID(brokerKL.key), ter(temINVALID), THISLINE);
+        }
     }
 
 public: