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Reported issue: Exception thrown when connecting the Node(Shapes with multiple path).
We can reproduce the reported issue when Node's Shape is with multiple path with Diagram. We have confirmed this as a defect and logged a defect report.
The fix will be available in our Service pack 1 of Volume 4 release which is scheduled to be rolled out on end of January 2019. Now, you can now track the status of your request, review the proposed resolution timeline, and contact us for any further inquiries through feedback link.