Hello! I am using a 5th gen iPad which can easily handle IF on it’s highest setting. I had this same problem, but found refreshing the app and restarting my iPad does the trick.
Hope this helps
On a side note, anyone that happens to look at this comment, I recommend tinkering with the app or your device a couple times before creating a support topic on here. I have had many problems so far, but I find testing and fixing problems on my own usually will fix it.