I've been trying to use my Orba and the Orba app on my iPad Mini 4, using iOS 13.7. I soon learned that connecting via a USB-C to Lightning connector doesn't work, so I tried using Bluetooth. Yep, it connects ok but I've noticed when loading presets that things go haywire sometimes. Occasionally I can upload a preset to the Orba, but at other times the transfer will hang, the connection/upload icon remains in place, with the blue line circling the icon. If I can get out of this screen I've found that the Bluetooth connection has dropped. Usually I cannot get out and the app hangs. Even if I shut it down, then restart it (even with a shutdown and restart of the Orba) the upload icon is still there. I have to shut down the iPad totally.
I get none of this when doing a wired connection to my MacBook Pro. I've yet to try Bluetooth on this machine because I'm not linking to a MIDI app other than the Orba one.