This forum is not an official forum, here the discussions are related mostly with xiaomi.eu custom ROM. As far as I know the xiaomi.eu have by default integrated call recording support into the system.
I'm not sure what were your steps, how and on what ROM did you installed the call recorder, but if you installed just an apk (an application) is not enough, because should be patched/installed and other packages which are deeply integrated into the operating system in order to support call recording.
Officially Chinese stock ROM and couples of other variants (not exactly sure) have this feature by default included in it (I think to Indonesian, Taiwanese and probably Russian firmware's too)