Quick answer: Insert a track before all other tracks in your arrangement, mute it and make sure recording is enabled.
Using LN Live with LogicWhen a keyboard is connected to the computer, Logic starts receiving data from it. This leads to both Liquid Notes and Logic receiving and processing the same data stream - consequently, Logic then responds to the uncorrected keyboard input.
To avoid this from happening, insert a track before all other tracks in your sequencer arrangement (at position one), mute it, and ensure that recording is enabled.
This will block unwanted sound outputs by the sequencer and is a known issue with Logic only.