diff --git a/gradle.properties b/gradle.properties
index 5f7f049..3a28aaf 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -2,6 +2,6 @@ seqraOrg=seqra
 
 seqraBuildVersion=2025.10.01.6b66511
 
-seqraIrVersion=2026.01.15.1f3bbc2
-seqraConfigVersion=2026.01.15.7ea9c38
-seqraUtilVersion=2026.01.15.c5a77a9
+seqraIrVersion=2026.01.21.17b5bbb
+seqraConfigVersion=2026.01.21.57ada3f
+seqraUtilVersion=2026.01.21.d61d52a
diff --git a/seqra-dataflow/src/main/kotlin/org/seqra/dataflow/ap/ifds/trace/MethodTraceResolver.kt b/seqra-dataflow/src/main/kotlin/org/seqra/dataflow/ap/ifds/trace/MethodTraceResolver.kt
index 6f8d03b..858cd46 100644
--- a/seqra-dataflow/src/main/kotlin/org/seqra/dataflow/ap/ifds/trace/MethodTraceResolver.kt
+++ b/seqra-dataflow/src/main/kotlin/org/seqra/dataflow/ap/ifds/trace/MethodTraceResolver.kt
@@ -1245,6 +1245,9 @@ class MethodTraceResolver(
                 }
 
                 val currentInitialFacts = object2IntMap<InitialFactAp?>()
+
+                // note: we always have zero fact
+                val zeroFactIdx = addEdgeInitialFact(currentInitialFacts, fact = null)
                 currentEdges.forEach { addEdgeInitialFacts(currentInitialFacts, it) }
 
                 val currentInitialFactsSet = BitSet(currentInitialFacts.size)
@@ -1257,6 +1260,8 @@ class MethodTraceResolver(
                             ?: return@cartesianProductMapTo
                     }
 
+                    // note: add zero fact since currentFactSet always contains it
+                    matchedInitials.set(zeroFactIdx)
                     if (matchedInitials != currentInitialFactsSet) {
                         return@cartesianProductMapTo
                     }
@@ -1281,8 +1286,8 @@ class MethodTraceResolver(
     private fun addEdgeInitialFact(
         initialFactIndex: ConcurrentReadSafeObject2IntMap<InitialFactAp?>,
         fact: InitialFactAp?,
-    ) {
-        initialFactIndex.getOrCreateIndex(fact?.replaceExclusions(ExclusionSet.Universe)) { return }
+    ): Int {
+        return initialFactIndex.getOrCreateIndex(fact?.replaceExclusions(ExclusionSet.Universe)) { return it }
     }
 
     private fun addEdgeInitialFactsIfRegistered(
diff --git a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRFactTypeChecker.kt b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRFactTypeChecker.kt
index bbc1c54..2fc00dc 100644
--- a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRFactTypeChecker.kt
+++ b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRFactTypeChecker.kt
@@ -276,20 +276,30 @@ class JIRFactTypeChecker(private val cp: JIRClasspath) : FactTypeChecker {
 
     // todo: fix config
     private val badElementAccessor = FieldAccessor("java.lang.Object", "Element", "java.lang.Object")
-    private val elementAccessors = listOf(
-        FieldAccessor("java.lang.Iterable", "Element", "java.lang.Object"),
-        FieldAccessor("java.util.Iterator", "Element", "java.lang.Object"),
+
+    private val elementBases = listOf(
+        "java.lang.Iterable",
+        "java.util.Iterator",
+        "java.util.Optional",
     )
 
-    private val badMapKeyAccessor = FieldAccessor("java.lang.Object", "MapKey", "java.lang.Object")
-    private val mapKeyAccessors = listOf(
-        FieldAccessor("java.util.Map", "MapKey", "java.lang.Object"),
-        FieldAccessor("java.util.Map\$Entry", "MapKey", "java.lang.Object"),
+    private val elementAccessors = elementBases.map {
+        FieldAccessor(it, "Element", "java.lang.Object")
+    }
+
+    private val mapBases = listOf(
+        "java.util.Map",
+        "java.util.Map\$Entry",
+        "org.springframework.http.ResponseEntity"
     )
 
+    private val badMapKeyAccessor = FieldAccessor("java.lang.Object", "MapKey", "java.lang.Object")
+    private val mapKeyAccessors = mapBases.map {
+        FieldAccessor(it, "MapKey", "java.lang.Object")
+    }
+
     private val badMapValueAccessor = FieldAccessor("java.lang.Object", "MapValue", "java.lang.Object")
-    private val mapValueAccessors = listOf(
-        FieldAccessor("java.util.Map", "MapValue", "java.lang.Object"),
-        FieldAccessor("java.util.Map\$Entry", "MapValue", "java.lang.Object"),
-    )
+    private val mapValueAccessors = mapBases.map {
+        FieldAccessor(it, "MapValue", "java.lang.Object")
+    }
 }
diff --git a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRMethodCallFactMapper.kt b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRMethodCallFactMapper.kt
index 0b3eb1f..e8d9207 100644
--- a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRMethodCallFactMapper.kt
+++ b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/JIRMethodCallFactMapper.kt
@@ -143,6 +143,7 @@ object JIRMethodCallFactMapper : MethodCallFactMapper {
 
         val callExpr = callStatement.callExpr
             ?: error("Non call statement")
+
         val returnValue: JIRImmediate? = (callStatement as? JIRAssignInst)?.lhv?.let {
             it as? JIRImmediate ?: error("Non simple return value: $callStatement")
         }
@@ -154,7 +155,7 @@ object JIRMethodCallFactMapper : MethodCallFactMapper {
             }
 
             is AccessPathBase.Argument -> {
-                val argExpr = callExpr.args.getOrNull(base.idx) ?: error("Call $callExpr has no arg $factAp")
+                val argExpr = callExpr.args.getOrNull(base.idx) ?: return null
                 val newBase = MethodFlowFunctionUtils.accessPathBase(argExpr) ?: return null
                 if (newBase is AccessPathBase.Constant) return null
 
diff --git a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/analysis/JIRMethodCallRuleBasedSummaryRewriter.kt b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/analysis/JIRMethodCallRuleBasedSummaryRewriter.kt
index a70557e..5c44701 100644
--- a/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/analysis/JIRMethodCallRuleBasedSummaryRewriter.kt
+++ b/seqra-jvm-dataflow/src/main/kotlin/org/seqra/dataflow/jvm/ap/ifds/analysis/JIRMethodCallRuleBasedSummaryRewriter.kt
@@ -41,7 +41,7 @@ class JIRMethodCallRuleBasedSummaryRewriter(
 
     private data class UserRuleDefinedAction(
         val rule: TaintConfigurationItem,
-        val positions: List<Position>,
+        val positions: Set<Position>,
         val controlledMarks: Set<String>
     )
 
@@ -55,7 +55,7 @@ class JIRMethodCallRuleBasedSummaryRewriter(
             val simplifiedCondition = conditionRewriter.rewrite(sourceRule.condition)
             if (simplifiedCondition.isFalse) continue
 
-            val positions = sourceRule.actionsAfter.map { it.position }
+            val positions = sourceRule.actionsAfter.mapTo(hashSetOf()) { it.position }
             result += UserRuleDefinedAction(sourceRule, positions, ruleInfo.relevantTaintMarks)
         }
 
@@ -65,7 +65,7 @@ class JIRMethodCallRuleBasedSummaryRewriter(
             val simplifiedCondition = conditionRewriter.rewrite(cleanRule.condition)
             if (simplifiedCondition.isFalse) continue
 
-            val positions = cleanRule.actionsAfter.filterIsInstance<RemoveMark>().map { it.position }
+            val positions = cleanRule.actionsAfter.filterIsInstance<RemoveMark>().mapTo(hashSetOf()) { it.position }
             result += UserRuleDefinedAction(cleanRule, positions, ruleInfo.relevantTaintMarks)
         }