Yes, we are aware that SPARK is not handling the Unit of Work functionality correctly.
The upcoming VS 2015 / .NET 4.6 / .NET Core 1.0 release will have this corrected.
In the meantime, we wrote a post in this forum on how to correct this (in C#).
It is not too difficult but if you use VB you will need to translate a few lines of C# to VB.
Hope this helps.
Jack Poorte, Apr 04, 2016