Pycharm 2018 throws on exception where 2017 doesnt.

I just installed PyCharm 2018, and am struggling with the debugger stopping on exceptions in a weird way. Running the code in the python shell as well as Pycharm 2017 or VS code I have no problems - Pycharm 2018 only. Is there a known bug or change that causes 2018 to behave differently than 2017? I have tried having the same project open in both editors at the same time, and only 2018 is giving me grief. 

Speficially I'm getting an exception from here (using boto3 dynamodb):
File "/usr/local/lib/python3.6/dist-packages/botocore/regions.py", line 122, in construct_endpoint
partition, service_name, region_name)
File "/usr/local/lib/python3.6/dist-packages/botocore/regions.py", line 135, in _endpoint_for_partition
raise NoRegionError()
botocore.exceptions.NoRegionError: You must specify a region.