I had been dealing with this issue for years. So there needs to be an article in Cakewalk knowledgebase.
I have 3 keyboards connected to a USB hub (Staples brand USB 3.0 hub with 7 ports). The hub is plugged into a USB 3.0 port on my computer. (I know I don't need 3.0, but the hub is 3.0 and I had problems plugging it into 2.0 port.)
My current workaround is:
1] Before I boot the computer (or resume from hibernation) I unplug all usb cables. (I unplug all cables from the hub, and unplug the hub from the computer)
2] After complete bootup, I plug hub into computer, then I plug the keyboards into the hub ALWAYS IN THE SAME PORTS, IN THE SAME ORDER.
3] If any keyboard gets unplugged, I do not plug it back in, because I know that will usually change the underlying windows port assignment and screw up all my projects midi assignments. Rather I close Sonar, unplug all keyboards and the hub, and plug in again in THE SAME PORT AND SAME ORDER as always. I then open Sonar, go to midi setup and check if the port numbers match the numbers and order I know it should be to work right (for me that is port 29, 30, 18). If not I completely shutdown and restart again from step 1.
A real pain in the ass. So I will look at trying to test the method described by geetsifly in his post above.
Hey
soens, what hub are you using and what is connected to it? I do not understand why you do not have the problem. For me simply using a hub does not prevent the problem. The keyboards get assigned crazy, unless I carefully use the method I described above.