When upgrading from 3.3.6 to 3.4.8, I found a very confusing problem about my scrollview items disappearing when you would reach a thirds of the list.
I managed to nailed it down to 3.4.3 UIPanel changes. I have looked at it but didn't managed to find the cause.
It happened in two different screens that had one thing in common, they were using a vertical scrollview.
I didn't managed to get exact reproduce steps but i you want, I might send you the scene in question in a private msg (the company won't allow me to make it public)