I see that can be the reason. How about using tf.keras.utils.plot_model() function.
See tf.keras.utils.plot_model  |  TensorFlow Core v2.5.0 3
tf.keras.utils.plot_model(
    model=your_keras_model, to_file='model.png', show_shapes=True, show_dtype=True,
    show_layer_names=True, rankdir='TB', expand_nested=True, dpi=96
)

expand_nested=True will expand your pre trained model