Notes are doubled after I save my music

I have the latest version (3.4.2.9788). I downloaded a midi file and plugged it into Musescore. The midi file was written with two Grand Staffs for piano (the bass clef had two staffs and the treble clef had two staffs). I don't know why. Musescore may have just recognized it as two Grand Staffs when it translated the midi file into the program since some of the notes in the bass clef go above middle-C and some of the notes in the treble clef go below middle-C. I combined them into two individual staffs. After doing that everything was fine. I did some extensive editing of the file. The main edit was that the first measure was blank. I moved the measures in the first bar over one and deleted the last measure. The problem happened when I saved the file and got out of the program. I restarted the program and called up the midi file. NOW, every note that plays, plays twice (like an echo).
I have tried everything I know to stop it, but nothing works. I selected the whole piece and cut all the measures. Then I did a paste into a brand new file. Didn't help. I tried deleting a few notes and re-writing them. Didn't help. I put the mid file into a different program that plays midi. It played fine (no doubling of the notes). When I look at the midi file as midi (no notes) the midi notes are not doubled.
I included my Musescore version of the file (with the doubling of the notes) and the original midi version as attachments.

Thanks