Cubase 3 for iPad

I purchased Cubase 3 for iPad and also a Steinberg UR44C audio interface. When using my iPad Pro (Gen 1) I have a .5 second delay (latency) between playing a music track, and recording a vocal track. When I try the same setup with a smaller iPad (gen 6) or my iPhone 7 Plus, I have NO delay (latency). All three devices are running the latest 15.3.1 software. Any ideas?

There’s separate forum section for Cubasis…

I will try to locate that area.