keras: AttributeError: 'Node' object has no attribute 'output_masks'

I use Keras pretrained model VGG16. The problem is that after configuring tensorflow to use the GPU I get an error that I didn’t have before when using the CPU.

The error is the following one:

Traceback (most recent call last):
File "/home/guillaume/Documents/Allianz/ConstatOrNotConstatv3/train_network.py",      line 109, in <module>
 model = LeNet.build(width=100, height=100, depth=3, classes=5)
File "/home/guillaume/Documents/Allianz/ConstatOrNotConstatv3/lenet.py", line 39,    in build
 output = model(pretrainedOutput)
File "/usr/local/lib/python3.6/dist-packages/keras/engine/base_layer.py", line 443, in __call__
 previous_mask = _collect_previous_mask(inputs)
File "/usr/local/lib/python3.6/dist-packages/keras/engine/base_layer.py", line 1311, in _collect_previous_mask
mask = node.output_masks[tensor_index]
AttributeError: 'Node' object has no attribute 'output_masks'

I get it after executing this code :

pretrained_model = VGG16(
    include_top=False,
    input_shape=(height, width, depth),
    weights='imagenet'
)
for layer in pretrained_model.layers:
    layer.trainable = False

model = Sequential()
# first (and only) set of FC => RELU layers
model.add(Flatten())
model.add(Dense(200, activation='relu'))
model.add(Dropout(0.5))
model.add(BatchNormalization())
model.add(Dense(400, activation='relu'))
model.add(Dropout(0.5))
model.add(BatchNormalization())

# softmax classifier
model.add(Dense(classes,activation='softmax'))

pretrainedInput = pretrained_model.input
pretrainedOutput = pretrained_model.output
output = model(pretrainedOutput)
model = Model(pretrainedInput, output)

I’ve got keras (2.2.2) and tensorflow(1.10.0rc1). I’ve also tried on keras 2.2.0 and same error. The thing is that the python environment I use works on others non-pretrained NN.

Moreover, I’m able to connect two homemade models. It’s only whith the pretrained ones there is a problem and not only VGG16.