You are right, in some cases the lists fail and it causes a big headache. Place a Label on the screen to control the beginning of the list index, the index in the ListViewer, and jn Firebase. You need constant monitoring to determine the source of the problem.
In case this can help you understand the bug;
If I ask the app to show the index (in this case in the alert field), the list works as intended, if after this i set the alert to the text it should display, it still works, I tried to reset the app, the phone, the pc, refresh the page, and it still works as intended, but another listviewer in another screen that showsbasically the same lists, doesn’t work while this one works.
After further testing I found that the lists stop working when you change the code in another screen
I solved with this since in my reference lists all entries are unique (the function is not actually needed):
where lista is the list you are picking the item from and oggetto is the item
@maxb, Is there any chance that you can post a link to a simple app which demonstrates the problem, along with specific instructions on how to reproduce the bad behavior? That will help us diagnose and fix the issue.