Lyric Verse White Space Doubling

I was writing down a song and trying to add two sets of slurs to moving thirds. I noticed that I could only add one slur for each note part. So I changed the two lower notes of the moving thirds to part 2 by control clicking the two notes and hitting the sequence ctrl+alt+2. It also changed the words of the first and third verse of the lyrics under these notes to green, which indicates part 2. Troublesome. I ignored it and added the slur. Suddenly there was an extra gap of white space below the third verse. I added another slur and the gap doubled. I hit undo by hitting control+z and the gap doubled again. Each time I did something, the gap doubled. I hit ctrl+z until the notes were all back to part 1 and the gap suddenly disappeared. I tried again. I moved the two lower notes into part 2 and it did almost the exact same thing. The only difference being it was not the first and third verse that changed to green, but the first and second verse. I added a slur and the gap appeared. The doubling of the gap occurred when I did anything. I undid it all and tried again. This time, when I changed the notes to part 2, it was the second and third verse that changed to green. The first verse was still part 1. There was no gap when I added the slur, and there was no gap at all when I added slurs or undid the actions. Each time I restart the program, I find a pattern. It starts with verses 2, 3. I undo and change the notes to part 2; it changes verses 1, 3 to green. I undo and change the notes to part 2 and it changes verses 1, 2 to green. It cycles through these three options after that. The gap appears if verse 1 is changed to green.

In case it helps, I included 4 screenshots. One is before I changed the notes to voice part 2. The next is after I changed the notes to voice part 2. The third is after I added the slur with the s key. The last is after I hit ctrl+z.