Change blocks on one screen and another screen errors

I have a screen that has a list and works great until I make a change to a different screen. I added an alert to a different screen and my screen with the list does not index correctly, always the last item is undefined.
How can this be???

same problem here with lottie animation blocks

This is so frustrating. I have subscribed for a month. I have had this app live for a year on the stores and now I need to make a couple of simple color changes and it destroys a listview page that has no relationship to the one I am changing the color of a field on. GRRRRR!!!. Thunkable please respond to this and help. A listview page that works in COPY A, I make a copy of COPY A and change a color of a couple of fields and change them from editable to non editable. Download to NOX or Phone and the listview now doesn’t index correctly.