Visual Studio 2013/2015 crashes when 7pace timetracker addin is installed

When the TimeTracker add-in (3.2.3.15521) for Visual Studio is installed, trying to bring up the properties of a project crashes Visual Studio.  This has been observed with VS2013U5, VS2015U3 and VS2017.  We have around 20 developers with VS2013U5, and about half of them have the crash but not the other half.  Disabling the 7pace addin fixes the crash issue.

The crash leaves these 2 events in the Event Log:

Application: devenv.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ArgumentException
   at EnvDTE._DTE.get_ActiveDocument()
   at VS.Integration.DteAccess.Providers.DteProvider.GetActiveDocumentName()
   at VS.Integration.VS2013.IntegrationUnit2013.GetActiveDocument(System.Object)
   at VS.Integration.VS2013.IntegrationUnit2013.<OnWindowActivated>b__20_0()
   at System.Threading.Tasks.Task`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(System.Threading.Tasks.Task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
   at VS.Integration.VS2013.IntegrationUnit2013+<OnWindowActivated>d__20.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(System.Threading.Tasks.Task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
   at Company.VSPackage4.TimetrackerPackage+<OnWindowActivated>d__15.MoveNext()
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0(System.Object)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
   at System.Windows.Threading.DispatcherOperation.InvokeImpl()
   at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at MS.Internal.CulturePreservingExecutionContext.Run(MS.Internal.CulturePreservingExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)

and

Faulting application name: devenv.exe, version: 12.0.40629.0, time stamp: 0x5590c8a4
Faulting module name: KERNELBASE.dll, version: 6.3.9600.18666, time stamp: 0x58f32841
Exception code: 0xe0434352
Fault offset: 0x00015608
Faulting process id: 0x31c
Faulting application start time: 0x01d337afb86633bb
Faulting application path: C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\devenv.exe
Faulting module path: C:\Windows\SYSTEM32\KERNELBASE.dll
Report Id: 1822c549-a3a3-11e7-8286-5cd998ae37d1
Faulting package full name:
Faulting package-relative application ID: