If there are no MonoBehaviours (C# scripts deriving from MonoBehaviour) in the Project, Asset Bundles cannot be loaded on iOS.

Steps to reproduce:
1) Open the attached project.
2) Delete /Assets/Scripts folder.
3) Switch platform to iOS.
4) Go to ASSETBUNDLES > Build Asset Bundles.
5) Build the project for iOS.
6) Run on a device.

Error is logged in Xcode's console:
Unable to load asset bundle: /var/containers/Bundle/Application/39871C90-61A0-4512-9F05-431E44BD02AB/assetbundles.app/Data/Raw/testbundle

This indicates that Asset Bundle can't be loaded.
The project uses a managed DLL instead of a regular script to load the bundles. Apparently, Asset Bundle assemblies are stripped when there are no MonoBehaviour scripts in the project. Scripts that don't derive from MonoBehaviour don't prevent the bug from happening.
This doesn't occur when Engine Code Stripping is disabled, or when Mono2x Scripting API is used. Does not reproduce on Android.
Note: the DLLs are not stripped since they are used to log the aforementioned error message.

Reproduced on:
2017.1.0a3, 5.5.1f1, 5.4.5f1, 5.3.7p4

Devices tested:
iPhone 7 iOS 10.3
LG Nexus 5 Android 6.0.1