We've got a potential deadlock issue, when calling UpdateAsync on a type that has RowVersion, there seems to be a deadlock. Here is a repro and here is the code in question. If I make the call sync then it throws the exception correctly when calling the async version I can see the exception in the Diagnostic Tools in Visual Studio.
Looks like it's an issue when manually handling async task flow, so I've changed it to use async/await in this commit..
This change is available from v5.4.1 that's now available on MyGet.