I'm experiencing the same problem: all VSTs are found by Cakewalk, I can see them listed in the Plugin Manager, but I can only find/use a few of them in the "Add Instrument" menu.
I just did a reset, followed by a scan. I am attaching the logs and would be very grateful if anyone would have the time to have a look to see what's going wrong.
Thank you.
VstScan.log
VstScanSandbox.log