diff --git a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/TransitionLinkerEnricher.java b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/TransitionLinkerEnricher.java
index 2241112..7f17edf 100644
--- a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/TransitionLinkerEnricher.java
+++ b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/TransitionLinkerEnricher.java
@@ -195,7 +195,7 @@ public class TransitionLinkerEnricher implements AnalysisEnricher {
     }
 
     private final java.util.Map<String, String> simplifyCache = new java.util.HashMap<>();
-    private final java.util.Map<String, Boolean> guardedCache = new java.util.HashMap<>();
+    private final java.util.Map<java.util.Map.Entry<String, String>, Boolean> guardedCache = new java.util.HashMap<>();
     private static final java.util.regex.Pattern SUFFIX_PATTERN = java.util.regex.Pattern.compile("(?i)(.+)(Event|Action|Transition|Command)(s)?$");
     private static final java.util.regex.Pattern FQN_PATTERN = java.util.regex.Pattern.compile("^.*\\.([A-Z0-9_]+)$");
 
@@ -217,7 +217,9 @@ public class TransitionLinkerEnricher implements AnalysisEnricher {
 
     private boolean isGuardedContains(String smEvent, String triggerEvent) {
         if (smEvent == null || triggerEvent == null) return false;
-        String cacheKey = smEvent + "|" + triggerEvent;
+        
+        // Use a strictly immutable pair to guarantee 100% collision-free caching regardless of string content
+        java.util.Map.Entry<String, String> cacheKey = new java.util.AbstractMap.SimpleImmutableEntry<>(smEvent, triggerEvent);
         if (guardedCache.containsKey(cacheKey)) return guardedCache.get(cacheKey);
         
         boolean result = calculateGuardedContains(smEvent, triggerEvent);
diff --git a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/matching/HeuristicEventMatchingEngine.java b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/matching/HeuristicEventMatchingEngine.java
index b996a7b..2c88a47 100644
--- a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/matching/HeuristicEventMatchingEngine.java
+++ b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/enricher/matching/HeuristicEventMatchingEngine.java
@@ -88,13 +88,14 @@ public class HeuristicEventMatchingEngine implements EventMatchingEngine {
     }
 
     private final java.util.Map<String, String> simplifyCache = new java.util.HashMap<>();
-    private final java.util.Map<String, Boolean> guardedCache = new java.util.HashMap<>();
+    private final java.util.Map<java.util.Map.Entry<String, String>, Boolean> guardedCache = new java.util.HashMap<>();
     private static final java.util.regex.Pattern SUFFIX_PATTERN = java.util.regex.Pattern.compile("(?i)(.+)(Event|Action|Transition|Command)(s)?$");
     private static final java.util.regex.Pattern FQN_PATTERN = java.util.regex.Pattern.compile("^.*\\.([A-Z0-9_]+)$");
 
     private boolean isGuardedContains(String smEvent, String triggerEvent) {
         if (smEvent == null || triggerEvent == null) return false;
-        String cacheKey = smEvent + "|" + triggerEvent;
+        
+        java.util.Map.Entry<String, String> cacheKey = new java.util.AbstractMap.SimpleImmutableEntry<>(smEvent, triggerEvent);
         if (guardedCache.containsKey(cacheKey)) return guardedCache.get(cacheKey);
         
         boolean result = calculateGuardedContains(smEvent, triggerEvent);