diff --git a/jOOQ/src/main/java/org/jooq/impl/DefaultExecuteContext.java b/jOOQ/src/main/java/org/jooq/impl/DefaultExecuteContext.java
index 21fe906b17..f6805e9596 100644
--- a/jOOQ/src/main/java/org/jooq/impl/DefaultExecuteContext.java
+++ b/jOOQ/src/main/java/org/jooq/impl/DefaultExecuteContext.java
@@ -37,6 +37,7 @@
  */
 package org.jooq.impl;
 
+import static java.lang.Boolean.FALSE;
 import static java.lang.Boolean.TRUE;
 // ...
 import static org.jooq.conf.SettingsTools.renderLocale;
@@ -352,7 +353,7 @@ class DefaultExecuteContext implements ExecuteContext {
         // [#7569] The original configuration is attached to Record and Result instances
         this.creationTime = configuration.clock().instant();
         this.connectionProvider = configuration.connectionProvider();
-        this.originalConfiguration = configuration;
+        this.originalConfiguration = initCaches(configuration);
         this.derivedConfiguration = configuration.derive(new ExecuteContextConnectionProvider());
         this.data = new DataMap();
         this.batchMode = batchMode;
@@ -368,6 +369,20 @@ class DefaultExecuteContext implements ExecuteContext {
         clean();
     }
 
+    /**
+     * [#18078] Some caches may have to be initialised in the global
+     * configuration, prior to creating the per-execution derived configuration.
+     */
+    private static Configuration initCaches(Configuration configuration) {
+        if (configuration.settings().getDiagnosticsConnection() == DiagnosticsConnection.ON) {
+            if (!FALSE.equals(configuration.settings().isDiagnosticsDuplicateStatements())) {
+                org.jooq.impl.DiagnosticsConnection.duplicateSql0(configuration);
+            }
+        }
+
+        return configuration;
+    }
+
     @Override
     public final ConverterContext converterContext() {
         return converterContext;
diff --git a/jOOQ/src/main/java/org/jooq/impl/DiagnosticsConnection.java b/jOOQ/src/main/java/org/jooq/impl/DiagnosticsConnection.java
index f6df4e1703..bdf529be2f 100644
--- a/jOOQ/src/main/java/org/jooq/impl/DiagnosticsConnection.java
+++ b/jOOQ/src/main/java/org/jooq/impl/DiagnosticsConnection.java
@@ -206,8 +206,12 @@ final class DiagnosticsConnection extends DefaultConnection {
         return DiagnosticsListeners.check(configuration.settings(), test);
     }
 
-    @SuppressWarnings("unchecked")
     final Map<String, Set<String>> duplicateSql() {
+        return duplicateSql0(configuration);
+    }
+
+    @SuppressWarnings("unchecked")
+    static final Map<String, Set<String>> duplicateSql0(Configuration configuration) {
         return (Map<String, Set<String>>) configuration.data().computeIfAbsent(
             "org.jooq.diagnostics.duplicate-sql",
             k -> synchronizedMap(new LRU<>(LRU_SIZE_GLOBAL))