I don’t fully understand the difference between a large phone and a tablet as far as rotation is handled. The app rotates and works fine on my phone and my wife’s. It also, I believe, works fine on my Amazon Fire HD 10.
That being said I recently purchased a Onn 10.1 Tablet (Walmart), which behaves incorrectly when rotated. It rotates when you rotate the tablet, but it has the orientation wrong. This may be a problem with Android 10? I’ve noticed one other application I have is confused as well. I’ve also noticed that a number of applications are not available yet for the tablet, when they work fine on the Amazon HD, or the older Samsung tablet we have.
Either way, it’s certainly not fixed and it seems like it could be due to changes in Android 9 or 10? At least other people are having similar problems so I don’t think it’s this specific tablet (which works fine for all but two apps).