I have in different patches at different times experienced that Keyboard (System Global) only work around half of the times I open my patch that has the node in it.
Same behavior when making a new node in a fresh patch it seems that only every other time it is working.
I have made sure that I only have one instance of the keyboard node even though it is no longer a singleton as mentioned in an earlier thread.
I am on win7 pro 64bit. I mostly run several instances of vvvv and I am suspecting that therein might lie some of the reason.