diff --git a/core/java/android/hardware/face/FaceManager.java b/core/java/android/hardware/face/FaceManager.java
index 3c3ba595f3fb9..385ad2d3577fe 100644
--- a/core/java/android/hardware/face/FaceManager.java
+++ b/core/java/android/hardware/face/FaceManager.java
@@ -790,6 +790,11 @@ public class FaceManager implements BiometricAuthenticator, BiometricFaceConstan
                 }
             }
         }
+
+        // This is used as a last resort in case a vendor string is missing
+        // It should not happen for anything other than FACE_ERROR_VENDOR, but
+        // warn and use the default if all else fails.
+        // TODO(b/196639965): update string
         Slog.w(TAG, "Invalid error message: " + errMsg + ", " + vendorCode);
         return "";
     }
diff --git a/core/java/android/hardware/fingerprint/FingerprintManager.java b/core/java/android/hardware/fingerprint/FingerprintManager.java
index dc1a50fa66161..87d45b9de745b 100644
--- a/core/java/android/hardware/fingerprint/FingerprintManager.java
+++ b/core/java/android/hardware/fingerprint/FingerprintManager.java
@@ -1386,8 +1386,13 @@ public class FingerprintManager implements BiometricAuthenticator, BiometricFing
                 }
             }
         }
+
+        // This is used as a last resort in case a vendor string is missing
+        // It should not happen for anything other than FINGERPRINT_ERROR_VENDOR, but
+        // warn and use the default if all else fails.
+        // TODO(b/196639965): update string
         Slog.w(TAG, "Invalid error message: " + errMsg + ", " + vendorCode);
-        return null;
+        return "";
     }
 
     /**