vscode-python: Debugger doesn't stop at breakpoint in a remote interpreter

Environment data

• VS Code version: 1.20.1
• Extension version (available under the Extensions sidebar): 2018.2.1
• OS and version: Windows 10
• Python version (& distribution if applicable, e.g. Anaconda): 2.7.14
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): N/A
• Relevant/affected Python packages and their versions: https://pypi.python.org/pypi/azure-iothub-device-client/1.3.0.0b0

Steps to reproduce:

It would be a little more steps to setup IoT Edge on your machine, so I just paste key files here (Let me know if you need other more details):

• Dockerfile: https://github.com/VSChina/iot-edge-python-docker/blob/master/modules/PythonModule/Dockerfile.amd64.debug
• Python module code: https://github.com/VSChina/iot-edge-python-docker/blob/master/modules/PythonModule/filter.py
• Launch.json: https://github.com/VSChina/iot-edge-python-docker/blob/master/.vscode/launch.json

Actual behavior

While when I try to debug a Python module in IoT Edge, I could attach the remote process in Docker, and see the console log in the Debug Console, and the breakpoint is red (which I think it indicates the source map is correct). However, the debugger did not stop at any breakpoint. Try it on both VS Code and VS Code Insider. And my another colleague also could not stop on breakpoint

BTW, sometimes, after wait for a long time, it will stop at while True of the https://github.com/VSChina/iot-edge-python-docker/blob/e817575416449751bd705528b2e024e196d1a52b/modules/PythonModule/filter.py#L132, I am not sure if it is related to time.sleep(1000)?

More info

• When I debug a simple hello world Python app, it is working well: https://github.com/Azure/edge-module-debug/tree/master/PythonModuleDebug
• When debugging https://github.com/DonJayamanne/vscode-python-samples/tree/master/remote-debugging-docker, I could step over/step into. however there is no highlight to indicate which line is stop at