Playback Issue

I'm using MuseScore2 on Windows 7, and I switched my instrument on the file to harp, transferring notes over before taking off the piano, and when I played back the first line (when there was no more written past that), I had no issues (Note: I had one rolled eighth-note chord (Second octave B) followed by a few more eigth-note octaves (second octave C) already written). Playback was fine, and I had no trouble at all. When I went onto the second line, which started with a rolled chord, and the same following top note (second octave F) in the octaves following, then going down to second octave E. When the chord in the measure was reached in the playback, a distortion occurred, with the slowing of tempo and buzzy, echoy sounds that will continue to occur no matter where I start playback again- IF there is still sound playing when I start playback again. The more I write, or playback, the more areas the distortion seems to be able to start at. It can be the line after, or the measure before the second line.
Also, I would have attached the file for testing, however, I could not figure out the process of doing so.