Opening BUN changes Multi in hardware Sampler

[gmp]

I have a client that's sending me BUN files and when I open it, it sends a midi message to my Akai S3000XL hardware sampler and it changes the preset for midi channel 1 and 2 to a different one. It leaves all the rest of the midi channel presets the same. I have to reload the Multi preset again to fix it. The midi out o my Motu goes to the Akai. Does anyone have a clue why this is happening? I don't see any changes in the settings for the Akai that will fix it, unless I'm missing something.