Why does Including Ads in project with IAP create duplicate arm64 symbol error

Project with IAP built with Unity 2018.3.12f1 on PC, moved to Mac and compiled with XCode successfully.

When I turn on Ads in services and repeat the build process I see “2 duplicate symbols for architecture arm64” and the Xcode build fails.

Same occurs with latest IAP and Unity 2019.1.2f1.