Well Tomek, it sounds to me that you have a problem with your MIDI file.
LP16 does not alter the playback of the midifile in any way, so it just plays out what the MIDIfile contains. Nothing more, nothing less.
From your description, I assume you have exported the midifile from your AW16?
Did you load this file into a regular DAW to see what actually is in that midi file?
I would suggest you carefully verify your midifile in a computer sequencer or DAW to verify