To reproduce:

1. Download and open attached "AarUnpackingTest.zip" project.
2. Go to build settings and make sure "Target Architectures" option is set to either ARMv7 or x86.
3. Build the project with Gradle.
4. After build is completed, extract the apk to see its contents.
5. Go to lib folder of the extracted content and notice that there are 2 folders for both platforms (ARMv7 and x86).
6. Notice that important.so file is present for both platforms even though only one was targeted.

Expected result: Unnecessary platform files are stripped from the main build. In this case, when selecting a platform, only for selected platform .so files are created and there are none .so files created for the other/untargeted platform.
Actual result: "important.so" file is created for untargeted platform.

Reproduced with: 2018.1.0a3, 2017.3.0b8, 2017.2.0p1, 2017.1.2p3, 5.6.4p2, 5.5.5p1.

Notes: build fails when building with internal build system selected.

Can be workarounded by specifying ABI filters in gradle script android.defaultConfig , for ex.,

ndk {
abiFilters "armeabi-v7a"
}

Verified with: 2018.1.0b1