Hum... sounds like you are pulling from the wrong rpc node (check on Settings of the app), which one are you using? rpc.esteem.app? I have an iPhone 8 and have no problems. If you are using rpc.esteem.app then try a different one to check if the same happens.
RPC Node?
LOL Man, I have no idea. I downloaded an app and started using it...
No worries...
Lets see, on you app after you have entered your pin code to unlock it,
Click on "your avatar image"(a left side menu should appear)->then "Settings"->(then check what's configured at the "Server" combo-box)
The RPC node should be set to the one I have told above. But you can use anyone's else. Although because it depends on the history of the node (aka being late or not) the app will react to the information received from that node.
Hope it helps.