diff --git a/OneSignalSDK/onesignal/notifications/src/main/java/com/onesignal/notifications/internal/common/NotificationFormatHelper.kt b/OneSignalSDK/onesignal/notifications/src/main/java/com/onesignal/notifications/internal/common/NotificationFormatHelper.kt
index 9e36f865a..80f02ce8a 100644
--- a/OneSignalSDK/onesignal/notifications/src/main/java/com/onesignal/notifications/internal/common/NotificationFormatHelper.kt
+++ b/OneSignalSDK/onesignal/notifications/src/main/java/com/onesignal/notifications/internal/common/NotificationFormatHelper.kt
@@ -42,6 +42,10 @@ internal object NotificationFormatHelper {
     }
 
     private fun getOSNotificationIdFromJsonString(jsonStr: String?): String? {
+        if (jsonStr == null) {
+            Logging.debug("Not a OneSignal formatted JSON. No 'custom' field in the payload.")
+            return null
+        }
         try {
             val customJSON = JSONObject(jsonStr)
             if (customJSON.has(PAYLOAD_OS_NOTIFICATION_ID)) {
diff --git a/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/common/NotificationFormatHelperTests.kt b/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/common/NotificationFormatHelperTests.kt
new file mode 100644
index 000000000..6670e55af
--- /dev/null
+++ b/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/common/NotificationFormatHelperTests.kt
@@ -0,0 +1,32 @@
+package com.onesignal.notifications.internal.common
+
+import android.os.Bundle
+import br.com.colman.kotest.android.extensions.robolectric.RobolectricTest
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+import org.json.JSONObject
+
+@RobolectricTest
+class NotificationFormatHelperTests : FunSpec({
+    test("getOSNotificationIdFromJson returns the id from custom") {
+        val json = JSONObject().put("custom", """{"i":"notification-id"}""")
+
+        NotificationFormatHelper.getOSNotificationIdFromJson(json) shouldBe "notification-id"
+    }
+
+    test("getOSNotificationIdFromJson returns null when custom is missing") {
+        val json = JSONObject().put("type", "call")
+
+        NotificationFormatHelper.getOSNotificationIdFromJson(json) shouldBe null
+    }
+
+    test("getOSNotificationIdFromJson returns null when custom is not JSON") {
+        val json = JSONObject().put("custom", "not-json")
+
+        NotificationFormatHelper.getOSNotificationIdFromJson(json) shouldBe null
+    }
+
+    test("isOneSignalBundle is false when custom is missing") {
+        NotificationFormatHelper.isOneSignalBundle(Bundle().apply { putString("type", "call") }) shouldBe false
+    }
+})
diff --git a/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/ingress/NotificationIngressTests.kt b/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/ingress/NotificationIngressTests.kt
index bc7a82dd5..4297b56cd 100644
--- a/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/ingress/NotificationIngressTests.kt
+++ b/OneSignalSDK/onesignal/notifications/src/test/java/com/onesignal/notifications/internal/ingress/NotificationIngressTests.kt
@@ -84,6 +84,17 @@ class NotificationIngressTests : FunSpec({
         NotificationIngress.pendingCountForTest(context) shouldBe 1
     }
 
+    test("FCM input without a OneSignal payload is rejected without scheduling") {
+        var scheduled = false
+        NotificationIngress.drainSchedulerForTest = { scheduled = true }
+        val bundle = Bundle().apply { putString("type", "call") }
+
+        NotificationIngress.persistFcm(context, Intent("com.google.android.c2dm.intent.RECEIVE"), bundle) shouldBe false
+
+        NotificationIngress.pendingCountForTest(context) shouldBe 0
+        scheduled shouldBe false
+    }
+
     test("dismiss input is persisted before scheduling") {
         var countAtSchedule = 0
         NotificationIngress.drainSchedulerForTest = {