AK::SoundEngine::IsInitialized() always returns false when called from UGameViewportClient::LostFocus()

Question

We are trying to suspend Wwise when the viewport is not in focus. Initially we used the AK::SoundEngine interface, but because of the problem in the title, we had no way to check if the engine was properly initialized. We tried the class FAkAudioDevice, which has a private variable named m_bSoundEngineInitialized. After adding a public getter to the class, the code is now working without any crashes.

Naturally, we'd like to avoid modifying the integration source. Is this a known issue, with IsInitialized(), and is there a solution?