I have a similar problem with one of my two Kempers. One of them functions just fine, in the other volume is only a fraction of what it should be when "X" is used as Effects Loop.
Same issue here. After updating Rig Manager does not recognize either on of my KPAs. Running 64 Windows 7. Had to uninstall the update, and re-install an older version. Contacted support - no response after 4 days. Frustrating to say the least.