Hi,
Your model includes TF ops that are not covered by the TFLite builtin op set. Please consdier enabling the Select TF ops. Select TensorFlow operators  |  TensorFlow Lite 1
converter = tf.lite.TFLiteConverter.from_saved_model(saved_model_dir)
converter.target_spec.supported_ops = [
  tf.lite.OpsSet.TFLITE_BUILTINS, # enable TensorFlow Lite ops.
  tf.lite.OpsSet.SELECT_TF_OPS # enable TensorFlow ops.
]
tflite_model = converter.convert()