Topological order error(Tensorflow,Keras)

ネットに掲載されていた、SegNetの一連のpythonコードを、あるマシンでは問題なく動かせたのですが、より新しいマシンにコード、データを移植して実行したところ、次のようなエラーが出てしまい、パフォーマンスが悪くなります（速度がすごく遅くなる）。

エラーメッセージ

2020-03-16 15:38:08.948802: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:697] Iteration = 0, topological sort failed with message: The graph couldn't be sorted in topological order.
2020-03-16 15:38:09.076589: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:697] Iteration = 1, topological sort failed with message: The graph couldn't be sorted in topological order.
2020-03-16 15:38:09.198882: E tensorflow/core/grappler/optimizers/meta_optimizer.cc:502] layout failed: Invalid argument: The graph couldn't be sorted in topological order.
2020-03-16 15:38:09.392132: E tensorflow/core/grappler/optimizers/meta_optimizer.cc:502] model_pruner failed: Invalid argument: MutableGraphView::MutableGraphView error: node 'loss/activation_9_loss/categorical_crossentropy/weighted_loss/concat' has self cycle fanin 'loss/activation_9_loss/categorical_crossentropy/weighted_loss/concat'.
2020-03-16 15:38:09.746898: E tensorflow/core/grappler/optimizers/meta_optimizer.cc:502] remapper failed: Invalid argument: MutableGraphView::MutableGraphView error: node 'loss/activation_9_loss/categorical_crossentropy/weighted_loss/concat' has self cycle fanin 'loss/activation_9_loss/categorical_crossentropy/weighted_loss/concat'.
2020-03-16 15:38:09.811513: E tensorflow/core/grappler/optimizers/meta_optimizer.cc:502] arithmetic_optimizer failed: Invalid argument: The graph couldn't be sorted in topological order.