Call recorder records my voice, but not incoming audio for other side of conversation. Using default settings on Android Oreo on a Nexus 6P.
I also faced this issue.
On outgoing calls I have recorded only my voice, no other's side voice.
It is regardless I use bluetooth headset or not.
It is worse. I called to someone a while ago and both voices are recorded. So it seems hard to debug.
I am not sure, but another call is recorded complete.
So far calls to unknown (not in address book) numbers are complete, but calls to numbers in address book are not.
I am not sure if this more that accidental coincidence.
None of the Nexus or Pixel devices support call recording. This will be same with all call recording apps and there is nothing we can do to fix it. You need to set audio source under ACR settings to MIC and enable loud speaker while on a call