I hope I am not repeating an already known issue here. I just updated to JustDecompile version 2011.2.1017.4. While looking at the disassembled C# code of System.Collections.Concurrent.ConcurrentBag in System.dll, I noticed that some of the member variables and method arguments which are of generic types have the type name truncated.
private volatile ThreadLocalLi<T> m_headList;
The above should be
private volatile ThreadLocalList<T> m_headList;
From what I can see (quick observation) this problem seems to be specific to the the nested types defined in the class. You will see the same issue with the nested Node<T> class, the class definition has the correct full name, but any references to the type are truncated.