Probably a bug which has been identified and will be fixed in OS 1.03 (coming soon) - in the meanwhile, try this: switch the Filter section to a different active control, e.g. press the Resonance button instead of Cutoff - now the LP should respond to incoming cutoff changes and you should be able to hear the result. This is happening because when RAC is active, the pot is directly in control of the active parameter, and the bug is that RAC is not being switched off automatically in response to incoming MIDI CC changes. So if you have just been tweaking the cutoff manually, RAC is active and it ignores the incoming CCs. Switching to a different function in the Filter section turns off the RAC for cutoff and then it can respond to CCs. Again, this has been fixed in the upcoming OS revision.