Training on custom dataset, I get AttributeError: 'Tensor' object has no attribute 'numpy'

[GuidoA]

Hello, and thanks for making a Keras version of DeepLab!
I've been trying to train your model on my custom dataset. All my images are 1088x2048x3, and I only have two classes. When I try to train the model on my dataset, I incur in these warnings:

which are then followed by this Traceback:

These are the loss, metric, and model.compile I'm using:

and these are the generators and model.fit_generator I'm using:

Do you have any idea what may be causing this? Would greatly appreciate any help!
Thanks.

[aliFrancis]

I have the same issue using fit_generator with a custom loader. Have you found a solution?