arm64 libraries throw warning "Cannot auto detect architecture for Android plugin"

I have a plugin that I build for arm-v7a and arm64-v8a and place in my project in the following paths:

-Assets

--Plugins

----Android

------libs

--------armeabi-v7a

-----------libmyplugin.so

--------arm64-v8a

------------libmyplugin.so

As is specified by the Android Native Plugin page in the Unity documentation.

However, when I launch my project, I get the following error:

Cannot auto detect arc$$anonymous$$tecture for Android plugin "Assets/Plugins/Android/libs/arm64-v8a/libmyplugin.so", defaulting to ARMv7

I haven't tried to build for Android yet, but I worry when I try to build an arm64 android executable I'm going to end up with duplicate symbols, and for the armv7a the build might try to include the arm64 library.

Is there a better way to explicitly report the target arch of a .so to Unity?

Thanks!