Passive one-sided communication, for a start. I no longer have access to the sort of systems on which that would fail, and I have never seen it used. When I did have such access, I did write code that caused its underlying assumptions to break, while investigating problems on the systems I managed.
You still haven't said what the actual problem is. I suspect that you just weren't using it properly if you broke the assumptions of MPI-2.2 RMA. It was extremely conservative.
I have to agree. It seems much, much more likely that you found a bug in the way a given implementation interacts with whatever you were doing with C or that your usage of RMA was not technically conformant. That said, if you have (or could reconstruct) an example that breaks the assumptions of MPI-2 RMA, it would be very beneficial to the standard if you would post that to the list. If the model is broken, we need to fix it! Keith