I have the same configuration with MacOS 10.14.6 EyeTV 3.6.9 (7522), unicable configuration with 4 frequencies, connected to Port 1 on 4Sat.
After update of Netstream App (Sorry I do not know at what version) problem was solved. Before it helped to boot iPhone more often.
It seems that issue appears for EyeTV 4 again. Hope that will be fixed in Netstream App soon. It looks like a initialzaition issue on iPhone App.
May be it will help to drop software from iPhone and reinstall. Afterwards configure unifiable and close Netstream on iPhone.
Hope that will help