That happened me once when my build folder was first used for building macOS and then I later changed it to build for iOS (i.e. CMake was accidentally ran without OGRE_BUILD_PLATFORM_APPLE_IOS defined).
libc++abi.dylib: terminating with uncaught exception of type Ogre::ItemIdentityException: OGRE EXCEPTION(5:ItemIdentityException): Workspace definition 'ShadowMapDebuggingWorkspace' not found in CompositorManager2::addWorkspace at OgreSource/OgreMain/src/Compositor/OgreCompositorManager2.cpp (line 498)