in my bike g5s plus, after 1 minute lowers the voice my or the other side of the line.
Moto G5s plus Android 7.1.1
Call recorder ACR
Unfortunately there is a bug with Android 7.1.1 that prevents call recording working reliably.
Setting recording delay to 3 or more seconds seems to help but not always.
This is same on all call recording apps and we hope will be fixed on Android 8
See https://bitbucket.org/copluk/acr/issues/1224 for the latest information about this issue