Deleting something near a triplet; also tempo as well

For both of these, go to the part called "Vocal"
1. On the attached file, go to measure 55 and at D, put a 4/4 time signature
2. At the previous measure, put a 2/4 time signature
3. Try to delete the bass clef of the measure that immediately precedes D.
4. The app will crash. Tried this with a few other sections of the song and it looks like this is an issue with how the app displays triplets (?). Please fix this ASAP as I need this for a class

As soon as you've figured that out,
1. Make any change to the song; it doesn't matter what, just don't save afterwards
2. Make sure that "View Invisible" is turned on
3. Go to measure 96 and hit play. Notice how the app completely ignores the tempo change
4. Undo the change you did earlier, and hit save. The app will actually adjust the tempo this time. Why?