I have the same problem downshifting into first when exceeding a certain speed. Like the previous post says - I think it 'locks' once you reach a set (althougt unspecified) speed.
The same thing happened in my last car so I don't think it's crossfire specific. This is only the second manual car I've owned but to me it seems normal. If your going too fast and you downshift into second the RPMS are going to go through the roof. So it makes sense to lock it, expecially being how short 1st gear is anyway.
Anyone else with more experience driving manual cars want to comment?