Hi! It's me again

Can not figure out what's wrong (Attach video).
I have two tabs (UIToggle, UIToggleObjects) with their content.
Content: Clipped Panel, ScrollBar etc. Both contents are identical in structure, they are two different Chats (Public and Room).
When I receive the desired event from the server, I turn on the second tab (UIToggle.value = true) and show another content (Room chat).
As you can see from the video, there is some effect, as if the contents of the list shows all. It is visible only when scrolling list (either manually or through a scroll) and tab changing in same time, and only in release build (in the editor, it is impossible to detect).
Thanks!