Check out How to deal with iMessage Navigation bar covering top of view bug by JR. Here is an excerpt:
iMessage has a bug where it doesn’t if you have something (like a search bar) pinned to the top of the view, it’s hides it when you transition from compact to expanded view.
The fix for now is to manually adjust the height on the top constraint so that when you are in expanded mode, you push it…
The full article is available here.
