iPhone 17 Pro, iOS 26.2. When looking at a post if I sleep my phone and unlock it, the Voyager window will look shrunken, not filling the screen. The top bar remains the same. Force quitting and reopening resolves the issue.
You also happening to me on iOS 18 when screen rotation is turned on; usually happens when I rotate by accident and it rotates back immediately. Only fix is swipe close and restart app