conversion error while converting tf saved model to tflite - tensorflow

Question

I am trying to convert a saved model tf to a tflite mode. I am getting following error in tensorflow c++ while conversion:-
tensorflow/contrib/lite/toco/tooling_util.cc:981] Check failed: name.substr(colon_pos + 1).find_first_not_of("0123456789") == string::npos (1 vs. 18446744073709551615)Array name must only have digits after colon\n'
Here is the source code :-
def convert_to_tflite_util(model_dir, output_dir):
tag_constants = set(["train"])
converter = tf.contrib.lite.TocoConverter.from_saved_model(model_dir, tag_set=tag_constants)
#converter = tf.contrib.lite.TocoConverter.from_saved_model(model_dir)
tflite_model = converter.convert()
Logs :-
2018-11-09 11:44:11.410085: I tensorflow/core/platform/cpu_feature_guard.cc:141] Your CPU supports instructions that this TensorFlow binary was not compiled to use: AVX2 FMA
INFO:tensorflow:Restoring parameters from /Users/deosingh/code/mldev/sensei-on-device/converters/deeplasso_converter/model/variables/variables
INFO:tensorflow:The given SavedModel MetaGraphDef contains SignatureDefs with the following keys: {'serving_default'}
INFO:tensorflow:input tensors info:
INFO:tensorflow:Tensor's key in saved_model's tensor_map: input
INFO:tensorflow: tensor name: data:0, shape: (-1, 320, 320, 4), type: DT_FLOAT
INFO:tensorflow:output tensors info:
INFO:tensorflow:Tensor's key in saved_model's tensor_map: output
INFO:tensorflow: tensor name: prob:0, shape: (1, 320, 320, 2), type: DT_FLOAT
INFO:tensorflow:Restoring parameters from /Users/deosingh/code/mldev/model/variables/variables
INFO:tensorflow:Froze 387 variables.
INFO:tensorflow:Converted 387 variables to const ops.
Traceback (most recent call last):
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 1664, in <module>
main()
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 1658, in main
globals = debugger.run(setup['file'], None, None, is_module)
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 1068, in run
pydev_imports.execfile(file, globals, locals) # execute the script
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)
File "/Users/deosingh/code/mldev/src/tf_to_tflite.py", line 112, in <module>
main()
File "/Users/deosingh/code/mldev/src/tf_to_tflite.py", line 108, in main
convert_to_tflite_util(args.src_dir, args.dest_dir)
File "/Users/deosingh/code/mldev/src/tf_to_tflite.py", line 91, in convert_to_tflite_util
tflite_model = converter.convert()
File "/Users/deosingh/code/mldev/venv/lib/python3.6/site-packages/tensorflow/contrib/lite/python/lite.py", line 439, in convert
**converter_kwargs)
File "/Users/deosingh/code/mldev/venv/lib/python3.6/site-packages/tensorflow/contrib/lite/python/convert.py", line 309, in toco_convert_impl
input_data.SerializeToString())
File "/Users/deosingh/code/mldev/venv/lib/python3.6/site-packages/tensorflow/contrib/lite/python/convert.py", line 109, in toco_convert_protos
(stdout, stderr))
RuntimeError: TOCO failed see console for info.
b'2018-11-09 11:44:18.328373: F tensorflow/contrib/lite/toco/tooling_util.cc:981] Check failed: name.substr(colon_pos + 1).find_first_not_of("0123456789") == string::npos (1 vs. 18446744073709551615)Array name must only have digits after colon\n'
None
Link to tensorflow source which is throwing this error.
The original model was in caffe , then was converted to tensorflow using mmdnn . Converter is complaining about name not being in the correct format i.e doesn't expect _ after : as per the tf source. Please let me know how to resolve/debug this error. Since the tf source which isthrowing this error is in c++ and I am invoking it through python I am not able to debug it through pycharm on macosx.