Can't save save/export and load a keras model that uses eager execution
I ran into the same problem and solved it by running the keras that comes with tensorflow:

from tensorflow.python.keras.models import Model, load_model


instead of:

from keras.models import Model, load_model


I suspect there's a version mismatch at the core of this problem. Loading the model worked with the Keras included with the current Tensorflow 2.0.0-beta1.