diff --git a/pkg/yqlib/lib.go b/pkg/yqlib/lib.go
index b051983c2c..876353ac1a 100644
--- a/pkg/yqlib/lib.go
+++ b/pkg/yqlib/lib.go
@@ -80,7 +80,7 @@ func recurseNodeObjectEqual(lhs *CandidateNode, rhs *CandidateNode) bool {
 		key := lhs.Content[index]
 		value := lhs.Content[index+1]
 
-		indexInRHS := findInArray(rhs, key)
+		indexInRHS := findKeyInMap(rhs, key)
 
 		if indexInRHS == -1 || !recursiveNodeEqual(value, rhs.Content[indexInRHS+1]) {
 			return false
diff --git a/pkg/yqlib/lib_test.go b/pkg/yqlib/lib_test.go
index a6ad5786c9..23ed2853d8 100644
--- a/pkg/yqlib/lib_test.go
+++ b/pkg/yqlib/lib_test.go
@@ -300,6 +300,24 @@ func TestRecurseNodeObjectEqual(t *testing.T) {
 	test.AssertResult(t, true, recurseNodeObjectEqual(obj1, obj2))
 	test.AssertResult(t, false, recurseNodeObjectEqual(obj1, obj3))
 	test.AssertResult(t, false, recurseNodeObjectEqual(obj1, obj4))
+
+	// A null key must not match a null value in the other map.
+	// Regression test for https://issues.oss-fuzz.com/issues/383860504
+	nullKey := &CandidateNode{Kind: ScalarNode, Tag: "!!null"}
+	nullVal := &CandidateNode{Kind: ScalarNode, Tag: "!!null"}
+	intKey := createScalarNode(2, "2")
+	intKey.Tag = "!!int"
+	intVal := &CandidateNode{Kind: ScalarNode, Tag: "!!null"}
+
+	mapWithNullKey := &CandidateNode{
+		Kind:    MappingNode,
+		Content: []*CandidateNode{nullKey, nullVal},
+	}
+	mapWithIntKey := &CandidateNode{
+		Kind:    MappingNode,
+		Content: []*CandidateNode{intKey, intVal},
+	}
+	test.AssertResult(t, false, recurseNodeObjectEqual(mapWithNullKey, mapWithIntKey))
 }
 
 func TestParseInt(t *testing.T) {
diff --git a/pkg/yqlib/operator_add_test.go b/pkg/yqlib/operator_add_test.go
index 9d4d6e7ba5..d5cff38d59 100644
--- a/pkg/yqlib/operator_add_test.go
+++ b/pkg/yqlib/operator_add_test.go
@@ -527,6 +527,18 @@ var addOperatorScenarios = []expressionScenario{
 		expression:    `.a += [2]`,
 		expectedError: "!!seq () cannot be added to a !!str (a)",
 	},
+	{
+		// Regression test for https://issues.oss-fuzz.com/issues/383860504
+		// Adding a map to itself must not panic when sequence keys contain
+		// single-entry mappings with a null key in one and a non-null key
+		// in the other.
+		skipDoc:    true,
+		document:   "? [{~: ~}]\n: v1\n? [{2: ~}]\n: v2",
+		expression: `. += .`,
+		expected: []string{
+			"D0, P[], (!!map)::? [{~: ~}]\n: v1\n? [{2: ~}]\n: v2\n",
+		},
+	},
 }
 
 func TestAddOperatorScenarios(t *testing.T) {
diff --git a/pkg/yqlib/operator_contains.go b/pkg/yqlib/operator_contains.go
index fa07d33fe4..dc7be8c86e 100644
--- a/pkg/yqlib/operator_contains.go
+++ b/pkg/yqlib/operator_contains.go
@@ -46,9 +46,9 @@ func containsObject(lhs *CandidateNode, rhs *CandidateNode) (bool, error) {
 		rhsKey := rhs.Content[index]
 		rhsValue := rhs.Content[index+1]
 		log.Debugf("Looking for %v in the lhs", rhsKey.Value)
-		lhsKeyIndex := findInArray(lhs, rhsKey)
+		lhsKeyIndex := findKeyInMap(lhs, rhsKey)
 		log.Debugf("index is %v", lhsKeyIndex)
-		if lhsKeyIndex < 0 || lhsKeyIndex%2 != 0 {
+		if lhsKeyIndex < 0 {
 			return false, nil
 		}
 		lhsValue := lhs.Content[lhsKeyIndex+1]
diff --git a/pkg/yqlib/operator_contains_test.go b/pkg/yqlib/operator_contains_test.go
index f714ace209..1fe1f96477 100644
--- a/pkg/yqlib/operator_contains_test.go
+++ b/pkg/yqlib/operator_contains_test.go
@@ -65,6 +65,16 @@ var containsOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!bool)::false\n",
 		},
 	},
+	{
+		// Regression: findInArray could match a null key against a null
+		// value at an earlier odd index, producing a false negative.
+		skipDoc:    true,
+		document:   "? 1\n: ~\n? ~\n: x",
+		expression: `contains({~: "x"})`,
+		expected: []string{
+			"D0, P[], (!!bool)::true\n",
+		},
+	},
 	{
 		description: "String contains substring",
 		document:    `"foobar"`,