Since updating to ArcGIS Pro 2.1.2 a custom Add-in built based on the Basic Map tool example from GitHub is failing. It returns "Exception while waiting for a Task to complete. Caller: ClearFinishedTasksImpl, File: C:\ArcGIS\ArcGISDesktop\ArcGISEditing\ArcGIS.Desktop.Editing\EditLib\Awaitable.cs, Line: 339. See the inner exception for additional information."
Any ideas or pointers on changes in the 2.1.2 SDK implementation that could have brought this about?
I have 2.1.2 of Pro installed and tried the 'Basic Map tool example from GitHub' and it worked fine without any problems. I assume at this point that your add-in problems are caused by some workflow related issues in your custom add-in code. Without a code sample of the offending snippet we can't get to the source of the problem. Maybe you can comment out portions of your code until you see the add-in work again. This should give you an idea as to the offending code snippet.