Wrong instruments in MIDI file
1. Open attached mscz (produced in 1.3).
3. Choose 'MIDI'.
5. Open MIDI.
Result: The trumpet appears as a string ensemble.
Also attached is the produced MIDI file.
Aria Maestosa 1.4.10, Finale 2014c.v4736, MuseScore 1.3 and Sibelius 7.5 show it as trumpet.
It's not reproducible if instruments without notes are removed, prior to export.
Using MuseScore 2.0 Nightly Build d48660b - Mac 10.7.5.