Rockin' Harmonika

I'm in the process of midifying one of my steirische harmonikas using an LPC1769 and DIN and DOUT modules. One of the goals is to be able to play a midi file from the SD card and have the buttons light up, showing what notes to play. The problem I'm having is that when the notes are triggered from the DIN module or from the virtual keyboard within Mios Studio, everything works as it should, but when they're triggered from a midi file on the SD card or from software like NI Kontakt, the LEDs will turn on like they should, but they won't turn off until I force them off via the control surface. I hooked an MD24 midi decoder module from Highly Liquid to the midi out of the LPC1769 and it works fine regardless of the midi source so this makes me think I have the DOUT modules configured wrong. I'm using the default configuration right now. Is there something I have to change ? I really don't want to use the MD24 decoder modules as they cost around $50 each whereas I can build a DOUT module for next to nothing, and I'd rather keep the whole project MIDIbox anyway ...